elements21 SCIENCE NEWSLETTER | 18| 19| 20||2007

Coating & Bonding Technologies Designing with Polymers Biotechnology Interfacial Technologies Inorganic Particle Design SCIENTIFIC FORUM Evonik Meets Science

1 EDITORIAL

Research RequiresDialogue

“The future begins here,” pledged Creavis employees and visitors at the inauguration of the Nanotronics Science-to-Business Center almost two years ago in Marl. It was written in red letters on the floor to the offices and pilot plants and underscored how highly we value research. For one Creavis project, the future has indeed begun. That project is the flexible ceramic separator SEPARION®, which enables the use of large-scale lithium-ion batteries. For this development, Evonik Industries and Prof. Paul Roth of the Univer- sity of Duisburg-Essen have been nominated for the Federal President’s Future Prize 2007. The nomina- tion honors both the scientific quality of the work, as well as the overall importance of the innovation to society, where it will create new long-term jobs. We are quite proud of this achievement. One of the factors in the success of this development has been close contact among the scientists, both internally and externally: The best ideas occur in direct dialogue, and short communication paths ensure that they are not lost. This is also the motivation for our Evonik Meets Science event. Continuing the tradi- tion developed at Degussa, we extended our fourth-ever invitation to some 200 scientists to join us to dis- Dr. Alfred Oberholz cuss current research topics, inspire new ideas, and gather feedback. Member of the This issue will give you a look at the topics we addressed – topics as diverse in their content as they are Executive Board of Evonik Industries AG in their stages of development: Some are still at the level of basic research, while others have already reached market maturity. We need both kinds – those that are in their infancy, and those that are appli- cation-oriented. The Nobel Prizes for the year 2007 in Physics and Chemistry provide impressive proof of this. While Peter Grünberg tracked an exotic phenomenon of sold-state physics and, in the process, made a discovery that revolutionized storage technology, Gerhard Ertl worked on an application-relevant issue: How metal surfaces enabled certain chemical reactions. His methods, however, came from basic research. Utilizing the strengths of university and industrial research alike, close contact among scientists, being open to new ideas – this describes our innovation philosophy. The Areas of Competence, the Science-to- Business Center, and Evonik Meets Science reflect this mindset. If you would like to learn more about the individual projects we discussed during the event, please do not hesitate to use the phone numbers and call the authors. Research requires dialogue. I hope you enjoy reading the current issue.

elements21 | 2007 4 FUTURE PRIZE BIOTECHNOLOGY Ceramic separator for lithium-ion batteries: 26 Tissue engineering: Conquering new territory Evonik team nominated for the german future prize with artificial organs 29 From extraction to fermentation: 8 EVONIK MEETS SCIENCE SCIENTIFIC FORUM contents New business prospects for specialty amino acids Intense dialogue between science and industry NEWS COATING & BONDING TECHNOLOGIES 30 Groundbreaking ceremony: 10 Highly reactive powder coatings expand the range of New production plant for methacrylates in Shanghai applications: Breakthrough in storage stability thanks to 30 PMMA molding compounds for flat panel displays: purified formulation New plant comes onstream in Taiwan 13 Automotive coatings – the silent revolution: 31 Evonik and TSM plan construction of an Although automotive coatings are already high in quality, integrated solar silicon production facility research continues at breakneck speed 31 R&D center expanded in Shanghai

The cover picture DESIGNING WITH POLYMERS INTERFACIAL TECHNOLOGIES symbolizes Evonik’s 16 New functions by programmed self-assembly: 32 Nanoemulsions for PEG-free cosmetics by five Areas of Compe- Macromolecular building blocks simple dilution with water made from polymer-peptide conjugates tence, which were 35 Water makes the diesel clean: Microemulsions reduce also the topics at 19 Drug delivery systems: the discharge of pollutants from engines Evonik Meets Science Conveying active ingredients to the cell interior (see p. 8) INORGANIC PARTICLE DESIGN NEWS 38 Evonik is the leading producer of inorganic particles: 23 Evonik Röhm: 100 years of thefuture Nearly endless applications 24 Creavis’ nanotronics summer school 41 Inorganic nanofillers for transparent polymers: links science and industry Invisible helpers for new functionalities 24 Threonine facility being expanded in hungary 25 Catalysis research: Evonik employees 44 EVENTS AND CREDITS receive renowned raney award

2 elements21 EVONIK SCIENCE NEWSLETTER news

+++ White Biotechnology: Evonik Industries Offers European Science-to-Business Award

European researchers interested in putting their exceptional scientific of the French company Metabolic Explorer; Prof. Heinz Saedler, direc- work in biotechnology into practice can look forward to support from tor of plant breeding research at the Max Planck Institute in Cologne; Evonik Industries. For the second time, the company is offering the Prof. Thomas Gutzwiller of the school for entrepreneurs at the Uni- European Science-to-Business Award, an innovation award that rec- versity of St. Gallen; and Steffen Klusmann, editor-in-chief of Finan- ognizes the market potential of an invention and assists its conversion cial Times Germany, which supports the Award as a media partner. to innovation. The award carries a prize money of € 100,000 and also Dr. Arend Oetker, president of the Donor’s Association for the Promo- includes management training at the University of St. Gallen. tion of Sciences and Humanities in Germany, is patron of the Award. “Our objective in offering the award is to build bridges between “This time, we decided that the focus would be on white biotech- university and industrial research,” said Dr. Alfred Oberholz, the mem- nology, because its environmental and economic advantages are in- ber of the Executive Board of Evonik Industries AG with responsibili- creasingly making it one of the key technologies of the 21st century,” ty for R&D in the Chemicals Business Area. “We want to motivate explained Oberholz. Experts predict that as early as 2010, between young scientific talent with an entrepreneurial spirit and help them 10 and 20 percent of all chemical substances will be produced by bio- swiftly convert their research results into products.” The European Sci- technological means. In specialty chemicals, which represents 40 per- ence-to-Business Award 2008 is aimed at scientists, entrepreneurs, cent of the chemical industry and is therefore its largest single sector, and the founders of start-ups who research or work in the field of growth is projected to increase significantly over the same period. white biotechnology, are 38 years old or younger, and work in a team In 2006, Russell Cowburn, professor of nanotechnology at with a maximum of three members. Entries must be received by Imperial College, London, accepted the first European Science-to- March 31, 2008. Business Award in the field of material sciences: “The Award helped Before the winner of the Evonik European Science-to-Business me enormously in developing and implementing my ideas for the Award in white biotechnology is announced in the fall of 2008, the manufacture of magnetic data storage,” he said. He also has a tip for entries will be thoroughly examined by a renowned jury from industry the Award winner in 2008: The prizewinner should just get used to and science. In addition to Evonik Executive Board member Dr. Alfred his newfound popularity and practice giving speeches. Oberholz, the members of the jury include Wim Soetaert, professor of More information on the Evonik European Science-to-Business biochemical technology at the University of Gent; Philippe Soucaille Award can be found at www.evonik.com/award.

+++ Evonik. Power to create.

Evonik was christened in a spectacu- lar event on September 12 in Essen. Evonik Industries AG is the creative industrial group which operates in three highly profitable, promising business areas: Chemicals, Energy, and Real Estate. The company is a global leader in specialty chemicals, an expert in power generation from hard coal and renewable energies, and one of the largest private resi- dential real estate companies in Germany. Evonik Industries is active in over 100 countries around the world. In fiscal 2006 around 43,000 employees generated sales of €14.8 billion and operating profit (EBIT) of over €1.2 billion. Evonik plans to enter the capital market in the first half of 2008

elements21 EVONIK SCIENCE NEWSLETTER 3 CERAMIC SEPARATOR FOR LITHIUM-ION BATTERIES Evonik Team Nominated for the

r. Andreas Gutsch and Dr. Gerhard Hörpel of Evonik Ceramic separators from Evonik enable Industries, along with Prof. Paul Roth of the Univer- the use of large lithium-ion batteries sity of Duisburg-Essen, are among the nominees for the German Future Prize 2007. The team impressed Other areas of application in which there is a demand for large- Dthe judges with its entry Nanoschicht mit Megaleistung scale batteries, however, have been barred to lithium-ion bat- (“Nanolayer with Megapower”), an application that enables the teries, because they could not meet the safety requirements. safer use of large-scale batteries, and opens up new opportuni- One of their weaknesses was in the battery separator. Conven- ties for the consumption of sustainable energy sources. tional separators, semipermeable polymer membranes used to Endowed with € 250,000, the German Future Prize of the separate the anode and the cathode in the battery, have two key Federal President is one of the most prestigious science and disadvantages: They are flammable and lose their stability at innovation awards in Germany: To be nominated, inventions temperatures above 140 °C (284 °F). This means that if batteries must not only be considered pathbreaking, but must also have equipped with these separators are overloaded, they can over- been developed to market maturity and contribute to job crea- heat, melt, and trigger a short circuit. tion. The most recent validation for the reputation of the Prize: The innovation nominated for the Future Prize, which is Prof. Peter Grünberg, Physics Nobel Prize recipient, had also based on a joint project among the German Research Founda- received the German Future Prize in 1998. “We are very happy tion, Evonik Industries, and seven universities, provides a remedy: to have been nominated. It reflects the revolutionary break- A new kind of separator, which Evonik Industries is marketing through in the field of lithium-ion batteries and, at the same under the name SEPARION®. SEPARION® is made of ceramic time, is an indication of the outstanding creative potential with- and polymers – two materials that are incompatible, given their in the Evonik Group,” said Dr. Werner Müller, CEO of Evonik differing temperature requirements. The combination of low- Industries AG. “In Kamenz, near Dresden, we are now com- temperature sintering and high-temperature plastic was made mencing serial production of battery components,” Müller con- possible through applied nanotechnology. Nanoparticles are a tinued. functional component of separators and, among other things, Lithium-ion batteries are considered the most promising ensure their material integrity, nanoporosity, and flexibility. candidates for the mobile energy supply of the future. They are In abuse tolerance tests, which simulate a variety of im- lighter, smaller, and more powerful than the other competitive proper uses, the batteries were overloaded, externally short- technologies: lead acid and nickel-cadmium batteries. They circuited, and had nails driven into them. The new separator have an exceptionally high energy and performance density, a passed all the tests with flying colors. Its most important features relatively high cell voltage of 3.6 volts, and also have a longer turned out to be high thermal resistance, chemical resistance, useful life. This is why almost all of today’s cell phones, notebook rapid wettability with electrolytes, outstanding charge behav- computers, and camcorders operate on lithium-ion batteries. ior, and complete temperature resistance.

4 elements21 EVONIK SCIENCE NEWSLETTER FUTURE PRIZE

German Future Prize

tial in the area of hybrid cars, for example, which combine the advantages of two different power trains. Depending on the driving situation, combustion engine and electric motor operate individually or in tandem. This promises not only better accele- ration, but above all fuel savings of up to 30 percent. According to estimates, more than 70 different models of hybrid car should be available in the year 2010. The overall sales figure is estimat- ed to be 1.2 million vehicles for that year, with 6.5 million fore- cast for 2015. Today, that figure is about 500,000. Hybrid cars, in particular, would profit from the new technology. These ve- Hybrid cars and tempo- hicles currently run on nickel-hybrid batteries, which are less rary power storage powerful and heavier than lithium-ion batteries and also con- in the use of regenerative energies are highly serve less fuel. Lithium-ion batteries, which have eliminated the promising fields of safety risk, would be revolutionary for this market. Evonik application for large- Industries is currently using a Honda Civic equipped with a bat- volume lithium-ion ® batteries with tery prototype to demonstrate that the SEPARION -based bat- SEPARION® tery technology is already application-ready and suitable for everyday use. The car has already logged 45,000 kilometers (about 27,962 miles). Another field of application just waiting for large-format Access opened to billion-euro market batteries is regenerative energies. Large lithium-ion batteries could make a major contribution to temporary power storage Evonik Industries has invested € 50 million in the development for utility-independent solar installations, for example, or to bal- and marketing of the new lithium-ion battery components, and ancing the utility supply by stabilizing the electricity grid. Polit- in the construction of production and pilot facilities – and all ically, a clear course has been set for renewable energy sources signs point to a substantial return on the investment. The newly such as the sun or wind for the sake of greater independence developed separator could be the key to acquiring the hybrid from fossil energy sources. This is why energy suppliers are obli- vehicle and stationary battery markets. According to forecasts, gated to integrate decentralized power supplies into their grids – the market for lithium-ion battery materials will grow from its for example, the excess energy from private photovoltaic units. current size of about € 1.4 billion to € 3.9 billion by the year 2015. While these measures mean increased operating expenses for The benefits would be felt by a host of industries along the grid operators and future expansion of the grid, the costs can be relevant value-added chains. There is enormous growth poten- reduced if large-format batteries are used for load leveling. >>>

BMBF initiative for lithium-ion batteries started Evonik Industries, BASF, Bosch, Volkswagen, and Li-Tec are embarking on an R&D initiative with the Federal Ministry for Education and Research (BMBF) for the development of “Lithium-Ion Batteries for Mobilizing Re- generative Energies of the Future and Increasing Efficiency in the Conversion of Fossil and Regenerative Energies.” The initiative is slated to last three years. The BMBF is funding the projects with some € 60 million.

Research initiative with the German Research Foundation (DFG) With regard to advanced development of the technology, Evonik has joined Nominated for the German Research Foundation (DFG) to support an initiative on the topic the German Future of “Functional Materials and Material Analytics for High-Performance Prize 2007: Lithium-Ion Batteries.” The objective of this initiative, in which several uni- Prof. Paul Roth (left), Dr. Andreas Gutsch versities and institutes are involved, is basic research on lithium-ion tech- (middle), and nology. Evonik is participating in the initiative with its own research project. Dr. Gerhard Hörpel (right)

elements21 EVONIK SCIENCE NEWSLETTER 5 These are just two areas in which growth is virtually pre- ty of three million square meters per year, the plant marks the programmed. Other conceivable areas of application would be completion of the first step from pilot to commercial production. recreational applications, such as boats or lawn mowers, where Where does the whole story begin? A small, creative, and market volumes are smaller, yet still nothing to be ignored. visionary group built around Prof. Michael Dröscher, head of In addition to separators, Evonik has expanded its portfolio Innovation Management Chemicals, identified the topic “Mem- for battery components with increased safety and power: The branes” and their market potential in the “Screening Commit- Kamenz site near Dresden already produces high-performance tee,” the predecessor of today’s Creavis. The researchers identi- anodes and cathodes. At the same site, the midsized company fied this topic at a time when lithium-ion batteries and their Li-Tec builds large-scale lithium-ion cells and batteries. As early application in automobiles were nothing more than a vision. as 2005, Evonik Industries had established a joint venture with The so-called Membrane Team turned this fantastic vision into Japanese battery manufacturer Enax as a forward integration reality. Under the wings of Dr. Gerhard Hörpel, the team con- measure. Ready-made electrodes are manufactured in China on sisted of Christian Hying, an expert in membrane technology this basis, while the joint venture markets powerful anodes and and today responsible for SEPARION® separator production; manganese-based cathodes. Volker Hennige, a ceramics expert, who currently heads the In all, Evonik has already produced several hundred thousand lithium-ion activities of Creavis in China; and Sven Augustin, square meters of separator film. Based on the positive response with his membrane application and market background, who is and in light of the great market potential, the company has installed currently responsible as a battery expert for automobile appli- an additional plant for producing the separator film. With a capaci- cations in Evonik’s Automotive Industry Team.

Rollable ceramics: The film used as a separator in lithium-ion batteries is ultrathin. Because of the strong response among battery manufacturers and the great market potential, Evonik has now installed an additional plant for producing SEPARION® and now has a capacity of three million square meters per year

6 elements21 EVONIK SCIENCE NEWSLETTER FUTURE PRIZE

The German Future Prize was awarded for the eleventh time in 2007. Four teams were nominated by Federal President Horst Köhler in Berlin for the finals on December 6. Through the project “Small Holes, Big Impact” by Nanion Technologies GmbH from Munich and the University of Freiburg, the develop- ment of new medicines can be accelerated and their effects on human cells tested more precisely, less expensively, and faster. Ultraprecise projection processes revolutionize the “Production of the Computer Chips of the Future,” – a project of Carl Zeiss SMT – and promise long-term security for the develop- ment of the technology. For the project “Light from Crystals” – a joint develop- ment of Osram Opto Semiconductors GmbH and the Fraunhofer Institute for Applied Optics and Precision Engineering – new manufacturing processes are used to generate ultraefficient, long-lived light sources that can serve as an envi- ronmentally safe substitute for conventional solutions. It is not possible to apply for the Prize; authorized institutions may submit to the jury up to three recom- mendations per call for application.

The development could create 1,000 new jobs in Germany

This team has acted as the nucleus for our lithium-ion activities. One hundred new jobs have already been created through the research and development of the new separators and additional battery components. If the level of growth comes even close to predictions, the number of jobs will increase tenfold in the next few years. The way appears paved for lithium-ion technology to bring back expertise and, with it, jobs to Germany. Part of those jobs are in the German state of Saxony, home of Li-Tec Battery GmbH & Co. KG, where Dr. Andreas Gutsch is the managing director. Li-Tec has produced lithium-ion cells and batteries in cooperation with Evonik at the Kamenz site in Saxony since October 2006. Gutsch was head of Creavis before moving to Li-Tec in 2007. “In just a few months, we have creat- ed 50 jobs in Kamenz. But our potential for this technology is far greater.” Dr. Gerhard Hörpel adds: “We are convinced of the enormous market potential of this application.” The problem: Skilled labor is hard to find. Gutsch: “We are desperately looking Cathode for engineers ready to join us on our growth path.” Applicants Separator must have a pioneering spirit and the courage to innovate. ● Anode

elements21 EVONIK SCIENCE NEWSLETTER 7 Intense Dialogue between Science

or the fourth time since 2001, the Chemicals Business “A chemical company used to do the research for new prod- Area of Evonik Industries AG has brought together re- ucts, but that’s now outdated,” explained Oberholz. “We now have searchers from science and industry for the scientific to move up the value-added chain and think in systems. System forum Evonik Meets Science. Some 200 renowned integration is becoming an increasingly important topic.” The Fresearchers from Germany and other countries took advantage work of the chemical industry, in particular, increasingly over- of the opportunity to learn more about current developments in laps with industries such as biotechnology, nanotechnology, medi- the field of chemistry by attending the technical presentations cine, photonics, and electronics. and discussions held on October 22 and 23. “Our experience Oberholz cited the example of lithium-ion batteries to ex- has shown that we have to link science and industry with each plain this approach: “To put it simply, we used to develop the var- other in a systematic way. An intelligent transfer of knowledge ious powders for making anodes, cathodes, and separators. To- keeps Evonik’s innovation engine running smoothly,” said Dr. day, however, even though we are a chemical company, we also Alfred Oberholz, the member of the Executive Board of Evonik have to understand the interplay of the components in a battery Industries AG with responsibility for R&D in the Chemicals cell if we want to be able to supply our customers and business Business Area, on the occasion of the forum. partners with new innovations.” This does not mean, of course, This year, the presentations at Evonik Meets Science focused that the company has to start manufacturing the cells or even the on five areas oriented to Evonik’s Areas of Competence. “Eighty batteries itself. Indeed, companies must always make a clear dis- percent of our core competencies are represented by these five tinction between what belongs to their core competencies and Areas of Competence,” says Oberholz. The areas are Coating & what does not. At the opening of the scientific forum, Dr. Klaus Bonding Technologies, Interfacial Technologies, Inorganic Engel, chairman of the Chemicals Business Area at Evonik In- Particle Design, Designing with Polymers, and Biotechnology. dustries AG, pointed out the importance of Evonik’s innovations On these platforms, Evonik combines the know-how, experi- in this area: “The market for lithium-ion batteries will grow to ence, and technologies of multiple business units in the Chem- ten billion euros over the next decade.” icals Business Area so that knowledge in the company can be In the Chemicals Business Area, about 2,300 employees work better and more selectively converted into concrete solutions. in R&D at more than 35 sites worldwide. The business area also

8 elements21 EVONIK SCIENCE NEWSLETTER EVONIK MEETS SCIENCE SCIENTIFIC FORUM

Dr. Klaus Engel, Member of the Executive Board of Evonik Industries AG and Industry

Some 200 researchers from Germany and abroad answered the invitation to Evonik Meets Science. Photo right: Dr. Alfred Oberholz, Member of the Executive Board of Evonik Industries AG

maintains over 250 partnerships with universities and other re- search institutes, in which it invests over €10 million per year. According to Oberholz, innovations are possible only if Evonik can collaborate on R&D with external research institutes. Such partnerships also require intense dialogue – for which Evonik Meets Science regularly provides the space. “Because people,” says Oberholz, “are the most important resource for innova- tion.” ●

elements21 EVONIK SCIENCE NEWSLETTER 9 HIGHLY REACTIVE POWDER COATINGS EXPAND THE RANGE OF APPLICATIONS Breakthrough in Storage Stability

DR. EMMANOUIL SPYROU

he economic importance of powder coatings has applies to polyurethane-based powder coatings, which not only grown continuously since the 1980s. Twenty years show good weather resistance but a balanced ratio of hardness ago, less than 200,000 metric tons were produced to flexibility. worldwide. Today, that figure has risen to about Because of the high reactivity of their starting compounds, T1,300,000 metric tons. At 38 percent, Asian manufacturers ac- however, these systems needed isocyanates – blocking agents, count for the largest share, followed by Europe with 35 percent. such as caprolactam, that prevent sudden cross-linking. These There are a number of reasons for the success of powder coat- blocking agents are released when coatings are cured, and so ings: They are environmentally safe, cost-effective, have good are undesirable both environmentally and economically. This is mechanical properties, and are easy to process. This especially why emission-free PUR powder coatings that emit neither sol-

Evonik has succeeded in significantly reducing the curing temperature for powder coatings with the help of special catalysts. This means it is now possible to coat temperature-sensitive substrates, for example high-quality kitchen furniture, with powder coat- ings that protect them reliably against UV light

10 elements21 EVONIK SCIENCE NEWSLETTER COATING & BONDING TECHNOLOGIES

Thanks to Purified Formulation

vents nor blocking agents were developed in the early 1990s. In Unit of Evonik Industries has succeeded in untying this Gordian the future, this unusually complete lack of emissions will gain Knot, and developed emissions-free, low-temperature-curing growing importance in the wake of increasingly more stringent powder coatings that nevertheless show remarkable storage environmental restrictions. stability. The mechanism of internal blocking consists in the forma- To better understand the reaction, researchers carried out tion of a four-membered heterocyclic compound from two iso- model tests in solvent, which simplifies the reaction sequence, cyanates each. At temperatures of 180 °C (356 °F) or higher, allowing it to be controlled with greater ease and precision. A these “uretdiones” can be broken down again uncatalyzed. The suitable catalyst, such as tetra alkyl ammonium carboxylate isocyanates that reform react under these conditions with resins (TAAC), which reaches at least moderate reactivity, is used to

Formation and cross-linking of uretdiones

O

O = O = = = C C + OH-Polymer = = -- R–N + N–R R–N- N–R N O–Polymer = - 1. Cleavage – C C H = = 2. Film building O O Isocyanates Uretdione Polyurethane

containing hydroxyl groups to form polyurethane compounds. lower the reaction temperature. The activity can be increased Now, through the use of special catalysts, it is also possible to significantly, however, by using another compound that con- lower the curing temperature considerably. As a result, temper- tains epoxide groups. After 30 minutes, the conversion rate ap- atures need be no higher than 130 to 140 °C (266 to 284 °F) – in proaches nearly 100 percent. unique cases, even 120 °C (248 °F). This represents a consider- In additional tests, researchers were able to prove that a able advantage over previous systems, because under these con- great deal of the reaction had already run in the first several min- ditions, even temperature-sensitive substrates like wood, MDF utes. With powder coating formulations that are homogenized plastics, and special aluminum alloys can be coated. at up to 120 °C (248 °F) in the extruder, this could lead to un- wanted preliminary reactions. Also, a slightly delayed curing is Low-temperature-curing powder actually an advantage in the case of powder coatings, because it coatings with good stability gives the powder melt more time for a smooth film formation. This is why the “catalyst duo” was expanded by a third compo- These highly reactive powder coating systems, with their low nent, which consists of a carbonic acid that does not significant- curing temperature, present not only advantages, for this feature ly impair the total reaction, but has a big impact on the progress used to severely limit the storage stability of powder coatings. of the reaction. Only when the acid is almost entirely consumed This is why, as a rule, they must be stored in a cool place and are, by reacting away internally does the reaction between the uret- therefore, expensive to handle. Glycidyl methacrylate (GMA) dione and alcohol really begin – and this results in the desired based powder coatings, for example, are used as a clear coating time delay. in high-quality automotive coatings. There are two reasons for Consequently, in addition to the reaction partners, at least the lack of storage stability: One is that undesired reactions can three additional components are needed for optimal control of occur even at room temperature. The other is that the coating low-temperature-curing polyurethane powder coatings: the ac- particles in these kinds of systems tend to sinter due to physical tual catalyst (TAAC, for example), an epoxide, and an acid. As a effects. For the first time, the Coatings & Colorants Business rule, the latter is already supplied through the hydroxyl >>>

elements21 EVONIK SCIENCE NEWSLETTER 11 polyester resins that are used. Depending on the manufacturing an important consideration in formulation, since epoxide has process, these resins still contain acid groups. always to be present in excess relative to the total quantity of The following reaction mechanism between these three catalyst and acid. components seems plausible: The carboxylate of the catalyst re- acts with the epoxide under formation of an alcoholate. The car- Additional improvements are boxylate is neutralized directly by the free acids, and a new car- already underway boxylate is formed. Only when this cycle is interrupted by the use of the entire acid can the alcoholate – the actual reactive It is also clear from the reaction sequence that, with differing component – unfold its effect. We must begin with the assump- concentrations and identities of the three components, a great tion that the reaction in the catalyst mixture is stoichiometric – many formulations are possible. Researchers worked with the liquid model system here, too, to achieve manageable results. In the final analysis, further development involves the optimization of each individual component – and, at the same time, all compo- nents, because whenever one component is changed, it affects Reaction curves in the catalysis of the uretdione and alcohol reaction. The desired time delay of the reaction occurs only with the addition of acid. the other two. The resin used also plays an important role, as it This is necessary for a good reaction and prevents pre-reactions during must ensure a smooth coating surface while also preventing the processing in the extruder powder coating particles from blocking or sticking. In all, the ■■ No catalyst ■■ + Catalyst changes take place in properties of reactivity, flexibility, reaction ■■ + Catalyst + Epoxid ■■ + Catalyst + Epoxid + Acid sequence, and storage stability. On the other hand, this also means that additional improvements are possible in the profile NCO [%] NCO concentration at 140 °C of characteristics of powder coatings, because many combina- 100 tions have not been tested at all yet. Developments in these areas are already underway. 80 Today, there are formulations available that completely cure within 30 minutes at 140 °C (284 °F) in a circulating air oven. 60 Their reactions progress well and they are also sufficiently flex- ible. Their storage stability is their most notable feature, how- 40 ever. These systems can be stored for two weeks at even 40 °C (104 °F) without any significant changes to their coating prop- 20 erties. Appearance (smoothness) and gloss, which are normally weak points of conventional low-cure powder coatings, are 0 particularly consistent. The stability achieved at 40 °C was 0 5 10 15 20 25 30 Time [min] previously unreachable for highly reactive emission-free powder coatings. In this regard, the new powder coatings are a milestone in tapping additional applications for environmental- Postulated mechanism of catalyst activation. The actual reactive component – the alcoholate – only reacts when the acid is consumed almost completely ly friendly powder coatings. More improvements in the formu- lations and the catalyst system are already underway, and will give these special coatings even greater momentum. ●

Epoxide

Tetraalkylammonium carboxylate

Alcoholate

Acid DR. EMMANOUIL SPYROU Emmanouil Spyrou works in research and development at Evonik’s Coatings & Colorants Business Unit, where he is responsible for the radiation curing and powder coatings research areas.

Carboxylate + Alcohol

+49 2365 49-2039 [email protected]

12 elements21 EVONIK SCIENCE NEWSLETTER COATING & BONDING TECHNOLOGIES

AUTOMOTIVE COATINGS

The Silent Revolution Although automotive coatings are already high in quality, research continues at breakneck speed

In the automotive industry, coatings and coating processes have achieved a high standard in terms of weather and mechanical resistance. What is more, they allow a wide array of hues and effects. But cost pressure, regulations, and the push to save energy are forcing researchers to search for new processes and materials.

PROF. DR. THOMAS BROCK

or many years, vehicle coatings have had a classical, pri- This classical coating system and its means of application are marily four-layer structure that protects the body of the set to undergo a number of changes over the next years, how- car against rust and mechanical damage, and provides ever. One factor will be cost pressure, which will have an impact color and different effects. The first layers applied to the on the choice of materials, energy consumption, and process Fmetallic carrier material made of steel, aluminum, or zinc, is a times. Legislative and health-related restrictions, as well as new phosphate layer and an electro-dip primer, which provide cor- requirements governing the quality of effects, functionality, and rosion protection and adhere extremely well to the metal sheet. performance, will also play an important role. A filler applied on top smooths any roughness in the undercoat One standard that the coatings industry has already con- so it cannot be seen when the very thin coating is applied. It also tended with for years is the use of lower quantities of solvents. protects the layers underneath against stone chipping. The base In the United States, the biggest demand is for high-solids sys- coat, which goes over the filler layer, is the color-bearing layer tems, which use special media with a tight relative molar mass, that is also responsible for a metallic or a pearl finish, for example. and two-component systems, depending on the area of applica- As the final layer, the clear coat protects the layers underneath tion. On the other hand, water-based and powdered coatings are against chemical and mechanical influences, and the effects of the preferred choices in Europe and, to some extent, Japan. Most light. water-dilutable coatings contain water-dispersed or emul- >>>

elements21 EVONIK SCIENCE NEWSLETTER 13 Nanofinishing for automotive coatings: interference on effect pigments coated nanothin

sified polymers. Practical experience has proven that changing to water-based coatings can reduce sol- vent emissions from production lines by two- thirds to three-quarters – even when the clear coat contains solvents and only the base coat, fil- ler, and electro-dip primer are water-based. New processes for drying and curing are also becoming more important – or at least the sub- ject of more intensive research. For “low-bake” processes, the industry is looking for ways to bake or cure at lower temperatures. Modified coatings are currently in various phases of testing. In some cases, drying processes such as those first used for coating wood – using dry, evenly warm air – can also be used for water-based automotive coatings. This technology, however, is specially suited to new plants, so only a few manu- facturers are currently using the process – Daimler, in its van factory in Düsseldorf, is one example. In automotive repair and in the refinishing phase of the production process, but above all in coil coating, near infrared technology (NIR®, KIR®), in which the coating is cured through energetic, shortwave IR radiation, is gaining prominence. The methods are not used (yet) in serial production, however, because of the fact that, for convincing From the driver’s perspective, the car coating must provide reliable protec- results, the distance between the metal sheet and the heat source tion against chemical and mechanical has to be precisely maintained – not an easy task given the ge- damage and the influences of light. ometry of a vehicle. It also has to look good. This way, he gets years of enjoyment from his car. In the near future, UV curing will almost certainly be the pro- From the industry’s point of view, cess of choice for vehicles in the upper price ranges, given the the materials and painting processes fact that coatings cured by this method can be further processed must also be cost-effective, consume little energy, and emit as little solvent quickly and show a high degree of scratch resistance. A two- as possible component isocyanate curing method is also used in the cavities

14 elements21 EVONIK SCIENCE NEWSLETTER COATING & BONDING TECHNOLOGIES

Clear coat Color-bearing base coat Filler layer Electro-dip primer Phosphate layer Metal

Most current automotive coatings have a four-layer structure, including the electro-dip primer, filler layer, color-bearing base coat, and clear coat

that cannot be easily reached by UV light. Compared to UV cur- trical coatings with electrically active polymers to replace ing, light radiation curing, which is still in the basic research stage, switches as pressure sensors. Both applications are still relative- would require fewer safety precautions and consume less ener- ly far from practical use, however. gy in a production line. In the intermediate term, the automotive industry will elim- Technically, the electrostatic spray coating of plastic parts is inate the filler from the current system of coating layers – some already feasible. But the conductive plastics required for the paint shops have already done so. The primer and base coatings method make the technology too expensive. Conductive under- will assume the tasks of the filler, and thereby help reduce ener- coats and new plastics with increased conductivity, as well as gy consumption by 30 percent and costs by 20 percent. Over the technical “tricks,” should pave the way for electrostatic plastics long term, the car body will not even have an electro-dip primer coating. coat. Instead, the metal will be pretreated by other “integrated Nanotechnology is also making its mark on the world of pretreatment” methods, including sol-gel processes or self- automotive coatings, where nanoparticles ensure, for instance, organizing monolayers. improved cross-linking of the coating layer. Tests in accelerated Whatever innovations arise over the next few years, the goal weathering plants and with scouring materials, for example, of the automotive industry is to lower costs and further simplify have shown that coatings with nano-linked polymers maintain processes. This can be done through fewer coating layers, for their shine longer than conventional clear coatings. Chemical example, but also through complete automation of the pro- compounds called “dendrimers,” whose structure resembles a cesses, as well as modular, decentralized production with pre- branched tree, in which the “branches” consist of repeating units cisely reproducible shades of color. Finer atomization of paint of the base molecule, could be attractive for base and clear coat- particles with ultrasound or laser for reproducibly thinner lay- ings. Dendrimers have been so expensive to produce, however, ers would also meet the industry’s objective. No matter what that research is concentrating on hyperbranched polymers, technique eventually prevails in the industry, it should, and will, which have similar properties, although they are neither as round go completely unnoticed by the consumer, as long as the nor as highly symmetrical as dendrimers. Even if these media changes are confined to the “interior life” of coating layers. To are expensive now, their use in the coatings of the future is as- the customer, then, the only improvement in the automotive sured. They could, for example, protect the base coat and the fil- coating will be its durability and looks – truly a silent revo- ler against stone chipping. “Nanofinishes” are already ensuring lution. ● higher soil repellency and longer life for transparent plastic parts such as headlight covers and glass. An already well-established direction of development for automotive coating chemistry has led to soft-feel coatings with skin-friendly “haptics,” such as on dashboards or door handle PROF. DR. THOMAS BROCK shells. While the industry relied on films and adhesive technolo- Thomas Brock has been Professor in Coating Technology at Niederrhein University of Applied Sciences in Krefeld gy for such applications in the past, it is now frequently turning since 1995. Previously, he spent ten years developing to plastic coatings embedded with polyurethane spheres. The automotive coatings for DuPont Performance Coatings, latter ensure that the coating surface feels soft. R&D is also con- the former Herberts GmbH. Most of his work is focused on measuring and testing technology, rheology, coating sidering functional surface effects for completely different production, and the various coating processes and types areas: One example is coatings with chemical fingerprints that of application. Currently, he is chairman of the “Coatings provide additional security against theft. In this application, the Chemistry” division (previously: APi) of the Society of German Chemists (GDCh). coating contains a chemical bar code that can then be read by +49 2151 822-4095 means of a scanning technology. Another example is piezoelec- [email protected]

elements21 EVONIK SCIENCE NEWSLETTER 15 NEW FUNCTIONS BY PROGRAMMED SELF-ASSEMBLY Macromolecular Building Blocks Made

Over millions of years, Nature has created proteins as a versatile platform of biopolymers. They follow a simple structural principle in which 20 different building blocks, natural amino acids, are combined into linear polypeptide chains. Despite the simplicity of the building block principle, peptides and pro- teins can be found in a broad range of applications, and perform a variety of different tasks in biologi- cal processes. They operate, for instance, as multifunctional systems that define the function of cells, the organization of tissues, the transport materials, or they catalyze chemical reactions as enzymes.

DR. HANS G. BÖRNER

he key to the function of proteins is their structure, peptides. Specific interactions can be used in a broad spectrum which is determined via a hierarchical structure for- of applications, such as organizing macromolecular building mation process over four distinguishable levels. The se- blocks (supramolecular chemistry with macromolecular LEGO® quence of the individual amino acids within the linear bricks), controlling the release of drugs from polymeric carrier Tpolypeptide chain determines the primary structure, while the systems, generating affinities to (bio-)surfaces, and stabilizing a formation of basic structural elements such as the α-helix and variety of interfaces, most importantly those between biological the -sheet governs the secondary structure. The three-dimen- systems and synthetic materials. sional organization of these simple secondary structure elements then defines the tertiary and finally the quaternary structure of Broad synthesis routes to versatile proteins. polymer bioconjugates Taking this simplistic structure formation principle into ac- count, the controlled integration of defined peptides into syn- At the Max Planck Institute of Colloids and Interfaces in Golm, a thetic polymers to transfer biological principles into synthetic research group is focussing on the synthesis and investigation of polymer systems is gaining importance. Hence, combining seg- highly defined polymer-peptide conjugates. Researchers devel- ments of monodisperse, monomer-sequence-controlled peptides oped and implemented a variety of access routes to integrate with synthetic polymer blocks enables one to access bioconju- monodisperse oligopeptides with defined monomer sequences gates. These might allow envisioning new possibilities for poly- into synthetic polymers. Primarily two approaches are utilized: mer chemistry by the direct translation of structural and func- A grafting method, in which synthetic polymers are polymerized tional principles of biology into synthetic polymer sciences. from a defined position of a peptide. In this method, initiator Peptide segments combine the possibility of defined self-assem- functionalities are integrated into an oligopeptide at a specific bly with the potential to actively interact with biological sys- sequence position. By using controlled radical polymerization tems. Thus, bioconjugates can be potentially used to program techiques, such as ATRP (atom transfer radical polymerization) structural formation processes in polymers and generate bioac- and RAFT (reversible addition-fragmentation chain transfer tive polymeric materials. In short, the goal is to understand and radical polymerization) the synthetic polymer block is synthe- control intermolecular interactions between sequence-defined sized in a well-defined manner.

Figure 2 1-Coupling/ligation 2-Macroinitiators 3-Inverse bioconjugation 4-(Macro)monomers Integration of monodispersed O oligopeptides with a defined

= Br

+ N NH = – monomer sequence (bio-

3 N 2 O = H segment) into synthetic poly- O mers. The synthetic methods developed allow broad access Polymerization Solid phase synthesis Copolymerization to various systems through coupling and polymerization strategies Adapted from: Lutz, Börner, Prog. Polym. Sci., 2007, doi:10.1016/j.progpolymsci. Biosegment 2007.07.005

Polymer bioconjugates (blocks or graft)

16 elements21 EVONIK SCIENCE NEWSLETTER DESIGNING WITH POLYMERS from Polymer-Peptide Conjugates

Acetylcholine receptor Green fluorescent protein Ribonuclease inhibitor Chaperon complex

Wormlike micelles Figure 1 Inspired by the structural principles of biology: By integrating defined peptide segments into synthetic Micelles Vesicles polymers, scientists from the Max Planck Institute for Colloids and Interfaces Research in Golm are opening up access to new, complex microstructures. Their work demon- strates that the biological principle “form follows function” can also be applied to the material sciences Adapted from: Förster et al., J. Mater. Chem., 2003, 13, pp 2671–2688, and Protein structures from PDB Amphiphilc AB-block copolymer

A different approach uses regioselective coupling methods, ponents in composite materials for lightweight construction, as including the highly specific “click” coupling reaction, to ligate nanowires for printable electronics, or as scaffolds for tissue polymers with defined end functionalities to complementary engineering for biomedical applications. groups in a peptide segment. These broad access routes allow for the integration of basically the entire variety of classical syn- Building blocks with switchable functions thetic polymers available (s. Fig. 2). Biomaterials are highly optimized to their purpose and fre- The functions of peptide segments in peptide-polymer conju- quently superior to synthetic materials. This results often from gates can be temporarily disturbed by selectively integrating hierarchical structures, facilitated and guided by proteins, pep- defect segments. This enables the realization of switchable build- tides, and saccharides. Scientists in Golm transferred this bio- ing blocks that have been demonstrated to be useful tools for logical concept of peptide-guided structural formation to synthet- peptide-guided microstructure control. The functions of the ic polymers and polymer materials. For that a variety of peptide- peptide, however, is only temporarily disturbed and can be based organizer units was studied, as depicted in Fig. 3 (p. 18). switched on again controlled via the pH value. Exploiting this The motif of the -sheet was closely studied as one of the concept conjugate systems composed of poly(ethylene oxide) three secondary structural elements, because interesting tape- and peptides have been realized that spontaneously organize like, fibrillary, or tubulary structures could be obtained. These into macroscopic tapes with lengths of several millimeters after are not only important structural and functional elements in switching the organizational tendency of the peptide segment natural materials, but they also offer a wide variety of possible ON. An analogous peptide segment attached to poly(n-butyl applications in synthetic materials. Such elements might allow acrylate) leads in organic solvents to the formation of nanosco- the generation of interesting properties, such as anisotropic pic spring structures as depicted in Fig. 4 (p. 18). strength and elasticity, defined positioning of chemical func- The combination of polymers and monodisperse peptides tionalities, and the directed transport of materials. This might allows for the expansion of the structural and functional space allow addressing applications such as, for instance, as fiber com- available for classical block copolymers, and potentially >>>

elements21 EVONIK SCIENCE NEWSLETTER 17 might broaden the platform of polymers significantly by exploiting the structure Figure 3 The concept of peptide-guided organization of synthetic polymers formation properties of peptides. The ra- Adapted from: Börner, Macromol. Chem. Phys., 2007, 208, pp 124–130 tional design in these bioconjugates is Peptide organizers Polymer-peptide conjugates Structures currently addressing the secondary struc- ture level, and transduction of informa- 1. Linear peptides tion in terms of complex, hierarchical self- assembly processes is still not fully under- stood. Even if the research is fundamental Nano and microtapes in nature to understand the basic interac- 2. Preorganized peptides tions and behaviors of such systems, it al- ready enables one to envision possibili- ties and potentials also interesting for industrial applications. Biomedicine and pharmacology, for example, offer fields Nanostructured tapes of application for bioactive polymer ma- 3. Cyclopeptides terials and highly defined functional polymers. Even now, bioconjugates com- posed of poly(ethylene oxide) and pep- tides are being tested as carriers for anti- Core-shell tubes tumor agents in cancer therapies. Appli- cation here can specially address lymphat- ically spread metastatic tumors that can- Figure 4 Peptide-guided organization of a polybutylacrylate peptide conjugate in organic not be easily reached via conventional solvents (diagram of the activation of the peptide organizer (left) and aggregation blood distributed carrier systems. to a nanoscopic coil spring [middle and structural model right]) It is predictable that polymer chem- istry with its inherent molecular weight AFM Structure model distributions will evolve to macromo- lecular chemistry with precisely defined molecules. Hence, the synthesis of fully on Distorted -sheet synthetic, monodisperse polymers with Switch defined monomer sequences will be one off Self-assembly of the upcoming challenges in polymer science. Completely unnatural polymer classes might be developed, which com- bine novel units capable of specific mo- lecular recognition with new monomer alphabets to fine-tune secondary interactions along linear poly- mer chains. The study of the sequence-structure-property re- lationships of these entirely synthetic macromolecules has to follow. Non-peptidic, monodisperse polymers with precise function- alities and functions offer enormous advantages. Particularly in DR. HANS G. BÖRNER the arreas of pharmacological and biomedical applications. Hans G. Börner is currently an Emmy Toxicological studies might be less expensive and licensing pro- Noether Fellow of the German Research cedures could be dramatically simplified. There are also several Foundation (DFG) and head of an inde- pendent research group in the colloid benefits foreseeable for materials sciences. Selectivity, specific- chemistry department of Prof. Markus ity, and, above all, bioactivity could be incorporated into mate- Antonietti at the Max Planck Institute for rials as realized already in biological materials. The methods Colloid and Interface Research in Golm. His research interests are focused on the introduced here might be attractive for the area of renewable synthesis, the characterization, and the raw materials, too. Polymers built from amino acids are most application of polymer bioconjugates to likely one of the first platforms to compete with classical poly- establish and control well-defined inter- actions in macromolecular systems. mers, made from fossil raw materials, and then well-defined +49 331 567-9552; [email protected] compatibilizers are required. ● www.mpikg.mpg.de

18 elements21 EVONIK SCIENCE NEWSLETTER DESIGNING WITH POLYMERS

DRUG DELIVERY SYSTEMS

With the help of low-molecular meth- acrylates, Evonik Industries researchers have created a new basis for highly specific drug delivery systems for future nucleic acid therapies. The company has also developed an additional platform for oral applications based on an endog- enous substance to improve the intake of active ingredients into the blood- stream via the intestine. In the future- oriented field of drug delivery systems, the company is the world market leader in the area of controlled release systems, and has already amassed many years of product and formulation know-how.

Conveying Active Ingredients to the Cell Interior

HANS-ULRICH PETEREIT, DR. NORBERT WINDHAB

he importance of effective active ingredients to the coatings that can be used to coat cores of active ingredients, or advances of modern medicine cannot be denied. Just in which active ingredients can be embedded. as much value is placed on the development of inno- EUDRAGIT® is made of polymethacrylates to which func- vative pharmaceutical forms, which make it possible tional groups have been added. These functional groups are Tto create the actual drug from the active ingredient. Advanced needed to equip the shell of these special pharmaceutical forms drug delivery systems ensure that an active ingredient is trans- with defined release mechanisms. The polymethacrylates of the ported from the site where it is applied to the site where it can EUDRAGIT® system are an excellent means of coating substrates, best fulfill its therapeutic function. crystals, pellets, tablets, or capsules with a shell that resists stom- These kinds of “shuttles” can, for example, transport an ac- ach acids. The choice of polymer allows selective control over tive ingredient unimpeded through the stomach and into the in- the release site of the active ingredient in the digestive tract. testine. Building on the many years of experience of the Pharma In principle, there are two different methods of controlling Polymers Business Line, the drug delivery platform EUDRAGIT® the release of the active ingredient: One dissolves the shell in a of Evonik Industries has already proven itself in a variety of ap- defined region of the human body in reaction to the pH value plications. The EUDRAGIT® family is based on pharmaceutical present in different regions of the human gastrointestinal >>>

elements21 EVONIK SCIENCE NEWSLETTER 19 tract, and the other controls the permeability of a polymer that is EUDRAGIT® NE 30 D, a methacrylic acid ester, belongs in this insoluble under physiological conditions by means of its class, and releases the active ingredient based on the thickness characteristic properties and the coating thickness. of the coating. One version of this system, in which the release Dissolution can be controlled through the pH value, for ex- of the active substance is triggered more flexibly not only by the ample, with the help of an amino function in a side chain of a cat- thickness of the coating but the permeability of the shell, is used ionic polymer such as EUDRAGIT® E. The coating is acid-soluble in EUDRAGIT® RL and RS. The effect is achieved with the aid of and is used for applications in the stomach, with the shell pro- quaternary ammonium groups in the pharmaceutical polymer. tecting against moisture, isolating taste, or preventing unwant- Building on these systems, the Pharma Polymers Business ed staining. By contrast, the associated anionic polymers in the Line has selectively developed drug delivery platforms. A good form of EUDRAGIT® L are equipped with carboxyl groups that example is EUDRACOL™ – a technology for targeted transport allow release in the basic environment. These kinds of coatings of the active ingredient through the digestive tract, with pH-de- are already used in medications that are resistant to gastric pendent and time-controlled release. The delivery system, ap- juices. After passing through the stomach, the tablets dissolve in plied in oral dosage forms, consists of an active ingredient core, the intestine as a result of the basic environment and release the which is enclosed in several layers of EUDRAGIT®. The outer active principle for absorption in the bloodstream. layer allows the core to be transported unchanged through the Diffusion-controlled release of active ingredients, indepen- stomach to the end of the small intestine, where it dissolves in dent of the pH value, offers an alternative to these systems. Such response to the basic environment. Later on in the process, the coatings enable the development of “delayed-release medica- release is diffusion-controlled through the second layer, so that tions,” which release the active ingredient over time rather than the active ingredient is solely released in the colon, where it all at once, thereby allowing it to work longer in the body. works on site or can be resorbed by the intestinal wall.

Interaction with biological membranes

The next logical step in the advanced development of drug de- livery technology is therapy on the cellular level. The big hurdle Catonic lipid here is the protective mechanism of the cell wall, which pre- vents foreign substances from entering the cell. Nature, how- ever, has left open a back door that allows many key nutritional substances and ingredients with biological mechanisms to be Active principle actively absorbed by the cells. On the other hand, viruses are able to exploit such mechanisms as gene shuttles, so to speak, or vectors to penetrate the cell wall. Given these circumstances, the Pharma Polymers unit tack- Anionic polymer led the question of whether drug delivery technology can be used to achieve targeted interactions with biological membranes that enable penetration into the cell. A ternary complex consist- ing of a cationic lipid, an anionic polymer, and an oligonucleoti- Ternary complexes as synthetic vectors. The complexes consist of a cationic lipid (dioleoyltrimethylammonium- de as active agent has proven the key to success, as it takes on the propane/ DOTAP), an anionic methacrylate copolymer and function of a non-viral, synthetic vector, and so prevents toxi- an antisense oligonucleotide as active agent. The system cological side effects of the shuttle. can be varied through the type of polymer, the amount of antisense oligonucleotide, and the charge ratio To develop a suitable system, researchers first started from the well-known fact that carboxyl functions interact with the phospholipids of the membrane and can destroy them. Anionic polymers are able to control this interaction with the membrane as a function of the pH level. Based on the company’s own ex- pertise, researchers then developed special anionic methacry- lates that show a lower molecular weight compared to existing EUDRAGIT® systems. The low molecular weight is important because the applica- tion is no longer oral, but must be administered parenterally by infusion or injection. The polymeric systems are structured like EUDRAGIT®, but show a decided difference in that the arrange- ment of the polymer chains in solution now depends on the pH value: When the pH value is high, the polymer chains are ex- panded. In acids, however, where the carboxyl residues are pre- sent in a non-dissociated form, a thick coil develops. This me- chanism affects the interaction with the membrane.

20 elements21 EVONIK SCIENCE NEWSLETTER DESIGNING WITH POLYMERS

The ternary complex consisting of lipid, polymer, and oligonucleotide enters Activity of T24 cells depending on cationic lipid and anionic copolymer, the cell as a Clathrin-Coated Vesicle (CCV) by endocytosis – a type of intro- measured at the enzyme expression. Complexes without copolymer and susception of the cell membrane, in which the complex enters the cell. In the simple mixtures of the components have no impact. Only the ternary interior of the cell an endosome is formed. Because of the differing pH values complex consisting of lipid, copolymer, and antisense oligonucleotide leads in the endosome and outside the cell, the active agent is immediately released to a significant reduction in enzyme expression from the endosome by polymer membrane interaction. Transport back out of the cell – exocytosis – and decomposition of the active ingredient in the functionally altered endosome, – the lysosome – is therefore unlikely

Extracellular pH: 7.2 Polymer alone Cell wall

Cationic lipids alone Exocytosis CCV Complexes without Release in the copolymer cytoplasm © Lysosome Complexes with Endosome copolymer and scrambled Endoplasmatic reticulum pH 5.8 oligonucleotide Complexes with copolymer and oligonucleotide 0 20 40 60 80 100 120 Lysis Enzyme expression [%] Nucleus Method adopted from Dean NM et al.

The key to genetic therapy is exocytosis: receptor-mediated livery platform for administering and increasing the activity of absorption of substances into the interior of a cell. The cationic nucleic acid agents. Through targeted release of active ingre- lipid contained in the ternary complex supports exocytosis. In dients in the cytoplasm, a new opportunity opens for selective the cytoplasm of the cell, this process leads to the formation of inactivation of malignant genes, for example – a process also an intracellular vesicle, the “endosome,” which transports the known as gene silencing. enclosed material to the lysosome or back to the cell wall and re- leases it there. Innovation coup with mother’s milk The pH value is 5.8 in the endosome, and 7.2 outside the cell. This means that the polymer passes through a conformation Another research project planned by Evonik’s Bio Science-to- change in the slightly acidic environment of the endosome, and Business Center aims to tap previously unfeasible oral applica- the active ingredient is released into the cytoplasma, the targeted tions for both new and existing active ingredients. And the frag- compartment. Exocytosis – the transport of the active ingre- ment of an endogenous protein supplies the key. Once again, the dient from the inside of the cell back to the outside – is therefore strategy is built on the ability of the EUDRAGIT® system to impossible. This mechanism allows the actual active ingredient, transport active ingredients unimpeded through the stomach the oligonucleotide, to diffuse to the cell core or the endoplas- and into the intestine. Because many active ingredients are not matic reticulum, the site of the cellular protein biosynthesis. absorbed well here, the system is also equipped with an endoge- The system is currently being tested using special blood can- nous peptide that promotes absorption into the intestinal cells cer cells (T24 cells). In vitro measurements reveal that the ac- and transport of the active ingredient from the intestine into the tivity of the cells remains unchanged when incubated, either with- bloodstream. This concept marks the first time a drug delivery out copolymer or as a simple mixture of these three substances. platform offering the characteristic therapeutic advantages for Only the addition of the ternary complex led to a significant the intestinal tract has become available for oral administration drop in the activity (about 50 percent) of these blood cancer of many known active ingredients. cells –proof positive that the specific oligonucleotide was actu- A fragment in human lactoferrin was identified as a suitable ally released in the cytoplasm and was able to interact in the peptide. This fragment makes up ten to 20 percent of the pro- desired way with the genetic material of the cancer cells main- tein content of mother’s milk and is also found in other bodily taining their vitality. Researchers had thus created a drug de- fluids and, naturally, in the milk of all mammals. Lactoferrin >>>

elements21 EVONIK SCIENCE NEWSLETTER 21 is an extremely large molecule, with a number of small subunits, strong stimulation of the intestinal cells. This stimulation results each of which performs different tasks. Certain subunits are in a large-volume absorption process, a type of macropinocyto- responsible for the transport of the iron, for example, while sis, that significantly increases the bioavailability of active in- others are able to interact with the DNA. The latter make up a gredients in standard tests, or at least makes it possible. small section of the protein molecule, which looks something In principle, the process is based on an elaborate trick, since like an electrical plug, and are arranged on the molecule’s surface. the cells recognize the shuttle – which is both invisible and a de- Because of the genetic code, this fragment is folded in a spe- coy – as one of their own. This absorption process was confirmed cific way. Amazingly, the same three-dimensional structure can many times in later tests. It is, therefore, possible to use a Trojan be found in the lactoferrin of all mammals, although the peptide horse to gain access to the interior of a cell through cell stimulation. displays different sequences of amino acids, depending on the Findings such as these could potentially open up completely genus. This three-dimensional structure was obviously con- new paths in pharmaceuticals – both for new medicines and for served over the course of evolution because of its function. many known active ingredients that are poorly absorbed by the The researchers of the Bio Science-to-Business Center have intestine on their own. These are listed, for example, in BCS now succeeded in loading various active ingredient particles Class 3, which includes therapeutic substances for which phar- with this human lactoferrin fragment and producing a number macists would like to see improved bioavailability. The present of substance samples for field tests. It also turned out that this findings raise hopes that, with the help of innovative drug de- small addition of peptide on the surface of the active ingredient livery platforms, advanced drug therapy will open up complete- particle is already sufficient to produce a shuttle that triggers ly new opportunities. ●

Sights are set on the next level of innovation: With the help of the EUDRAGIT® A certain segment of the human protein lactoferrin (left) enables drug delivery system and an endogenous peptide, researchers in the Bio the absorption of various active ingredients into the intestine. Science-to-Business Center aim to improve the absorption of active ingredients The photo on the right shows in vitro how a fluorescent pigment in the intestine, and thereby increase bioavailability. Prof. Dr. Ulrich Schubert, was fed into the cells Jena, and Prof. Dr. Roland Brock, Tübingen, among others, are involved in the project. Dr. Benedikt Hartwig is the project manager at Evonik

EUDRAGIT®

Stomach Intestine Cell Blood

HANS-ULRICH PETEREIT DR. NORBERT WINDHAB Hans-Ulrich Petereit has headed Norbert Windhab is Senior Manager Research, Development, and Technical Biotechnology in Evonik’s research unit Service for the Pharma Polymers Creavis Technologies & Innovation in Business Line of Evonik’s Specialty the Bio Science-to-Business Center, Acrylics Business Unit since 1995. where his responsibilities include human His areas of responsibility include studies, new pharmaceutical syntheses, development of drug delivery systems. and nutritional supplements.

+49 6151 18-4396 +49 2365 49-5457 [email protected] [email protected]

22 elements21 EVONIK SCIENCE NEWSLETTER news

+++ Evonik Röhm: 100 Years of the Future

The company was started 100 years ago as a manufacturer of enzy- larger quantities of acrylic acid esters and, finally, developed for the matic leather tanning chemicals (mordants). Today, it is the global automotive industry a completely transparent safety glass with an in- leader in methacrylate chemistry: Evonik Röhm GmbH, which repre- terior acrylic layer, the production of which started in 1928. sents the Methacrylates and Specialty Acrylics Business Units of The breakthrough came in 1933 with the registration of the trade- Evonik Industries. “With sales of over € 1.6 billion, these two busi- mark for PLEXIGLAS® – the first completely transparent plastic, which ness units generate 15 percent of the chemistry sales of the new was originally painstakingly polymerized between two plates of glass. Evonik Industries, and make an above-average contribution to the Even back then, the cast plates impressed the beholder with the same Group result,” said Dr. Manfred Spindler, member of the Manage- qualities of transparency, brilliance, unsurpassed aging resistance, ment Board of Evonik Degussa GmbH, at the event celebrating the formability, and fracture resistance that are valued today. “The success 100th anniversary of Evonik Röhm in Darmstadt in late September. of plastics was possible largely because of the evolution of improved Three hundred guests were in attendance, including international methods for systematically processing them into finished or semi-fin- customers, representatives of politics and associations, as well as Vera ished products,” said Albrecht. Today, multiunit injection-molding Röhm and Dr. Axel Röhm, the grandchildren of company founder machines are taking over complex manufacturing processes and thus Otto Röhm. helping develop increasingly efficient solutions in large-scale produc- The event included a scientific colloquium, during which Dr. Klaus tion. Extrusion technology has also reached a quality very close to that Albrecht, head of Innovation Management for the Methacrylates of cast plates. Only for the kind of ultrahigh-molecular PMMA grades

Dr. Klaus Albrecht, head of Innovation Management for the Methacrylates Business Unit (left) and Dr. Manfred Spindler, member of the Management Board of Evonik Degussa GmbH

Business Unit and head of R&D in the Molding Compounds Business used in aquarium panes or airplane windows does casting remain the Line, led some 50 university scientists through the company’s history. method of choice. “One of Otto Röhm’s great achievements was to help further our But Evonik Röhm has long offered more than just the high-quality understanding of polymers by systematically working with acrylates,“ plastic PLEXIGLAS®. The Pharma Polymers unit produces methacry- said Albrecht. Once the new company – established on September 6, late-based polymer coatings that can be used to control the rate or lo- 1907 by Röhm and his friend Otto Haas for the manufacturing of cation of the release of active ingredients, and the subsidiary Evonik enzymatic products – had made enough income for research purposes, RohMax supplies oil additives that help improve the viscosity of lubri- he put together a research team that continued his work since the cants and gear and hydraulic oils; they ensure that oils have uniformly 1910s on the synthesis and polymerization of acrylic acid, and on meth- good lubrication properties over a range of temperatures. acrylic acid as a somewhat later focus. All activities were based on “Otto Röhm was ahead of his time,” said Spindler. “He was solid- Röhm’s 1901 dissertation “Polymerization Products of Acrylic Acid.” ly convinced that the results of his dissertation amounted to a technol- The team systematically studied the properties of acrylic plastics ogy platform that he could use to build a completely new business – and were not discouraged by the lack of technical difficulties. Indeed, twenty years before the seminal work of Hermann Staudinger laid the Röhm described a synthesis pathway for acrylic acid from ethylene groundwork for polymer chemistry.” Success has proven him right – early on. Because there was insufficient research on stabilization of today, Evonik, with its Methacrylates and Specialty Acrylics Business the monomers, the compounds had to be cleaned in small quantities Units, is the global leader not only in methacrylate chemistry, but also in completely darkened laboratories. Otherwise, spontaneous poly- in specialty monomers for paints, dispersions, and adhesives, and is merization would occur. Little by little, the team was able to produce the world’s second-largest supplier of PMMA molding compounds.

elements21 EVONIK SCIENCE NEWSLETTER 23 Creavis discussed results from the projects of Evonik’s Nanotronics Science-to-Business Center in Marl with about 80 university scientists

+++ Creavis’ Nanotronics Summer School Links Science and Industry

What are the latest developments in the field of printable electronics? The annual Nanotronics Summer School, a key component of What materials can be used to produce innovative, flexible flat screen Evonik’s science-to-business concept, helps promote a fast and com- displays? What materials can be used to produce flexible, inexpensive prehensive exchange of experience and information within the Nano- solar cells? These and other questions were the focus of Nanotronics tronics Science-to-Business Center cooperation network. As a place Summer School 2007, which Creavis Technologies & Innovation, the where experts from industry and scientists from a variety of research R&D unit of Evonik Industries, held in September in a complex locat- institutes can conduct an open exchange on current research results, ed just outside the gates of the Marl Chemical Park. the Nanotronics Summer School and the partnership network it is About 80 scientists from 25 universities and research institutes based on are unique in the German research landscape. gathered with experts from Creavis to discuss current developments The workshop was set up like a scientific symposium: The 27 and results from the projects of the Nanotronics Science-to-Business presentations covered such topics as the optical properties of silicon Center. Other participants included research groups working with quantum dots, conduction mechanisms and structural elements of Creavis in bilateral research partnerships, and representatives of the nanoparticulate semiconductor layers, improving the conductivity of Dispersion Systems for Electronics Applications Graduate College of ITO nanoparticle coatings on polymer substrates, and the processing the University of Erlangen-Nuremburg, and “Nanotronics – Photo- of nanoscale particles to printed layers. Another highlight of the Sum- voltaics and Optoelectronics from Nanoparticles” of the University of mer School was two poster sessions devoted to an in-depth discussion Duisberg-Essen, which are both sponsored by the German Research of joint research activities, which also allowed project participants to Foundation (DFG). become better acquainted. “Our goals for the development of nanotechnological solutions In the Nanotronics Science-to-Business Center, Creavis works for future electronics applications are so ambitious that we can only with scientists and internationally renowned universities, and coop- reach them together,” stressed Dr. Harald Schmidt, head of Creavis erates with two graduate colleges sponsored by the German Research Technologies & Innovation, in his welcome address. “Our objective is Foundation. The project is funded by the State of North Rhine-West- to forge the optimal link between science and industry, so that new phalia, and co-financed by the European Union. Thanks to the part- scientific developments can be rapidly converted into new products,“ nership, the company benefits from an immediate transfer of top re- explained Dr. Ralf Anselmann, head of the Nanotronics Science-to- search, and young scientists from a better understanding of industrial Business Center. practice.

+++ Threonine Facility Being Expanded in Hungary

Evonik’s Feed Additives Business Unit is expanding the capacity of its Wennemer, president of Feed Additives, explained. “This investment L-threonine facility in Kaba, Hungary, to 20,000 metric tons per year. represents another cornerstone in our amino acid growth strategy,” In addition to the capacity enlargement, the company will upgrade Wennemer continued. production technology and process automation, as well as product “Relative to the capital outlay for a greenfield plant of that size, the design, to optimize plant efficiency further. Operated by the subsidiary specific investment cost at Kaba is significantly lower. This cost bene- Evonik Agroferm, the plant is scheduled to go on stream by the end of fit combined with the fermentation expertise and skills of our Hun- this year. garian workforce give Evonik a sustainable competitive advantage,” “Right from the beginning, in spring 2004, when Evonik acquired Sigmar Eisele, president of Evonik Agroferm, said. the Agroferm site, it was our intention to transform the former lysine “Nowadays, Europe accounts for over 50 percent of the global production into a state-of-the-art L-threonine plant,” Dr. Hubert threonine market and provides further growth potential, especially in

24 elements21 EVONIK SCIENCE NEWSLETTER news

Evonik’s Kaba, Hungary, site, where threonine production is being expanded the Eastern area. Additionally, the relative importance of Asia and Latin respond in a flexible manner to increasing customer demand. Hence, America is expected to rise overproportionally in the coming years,” the company has the technical capability for de-bottlenecking its two Dr. Thomas Kaufmann, vice president of Marketing, explained. threonine production sites further. The Kaba site is Evonik’s second state-of-the-art threonine pro- L-threonine and L-tryptophan are protein building blocks. They are duction facility in Europe, bringing the company’s total capacity to essential in today’s nutritional concepts for balancing the amino acid 40,000 metric tons per year. The new threonine production line also levels in animal feeds and for optimizing livestock production while frees up fermentation capacity to be used for production of trypto- decreasing nitrogen excretion, and thereby reducing the environmen- phan and other amino acids. This modular concept allows Evonik to tal impact of livestock farming.

+++ Catalysis Research: Evonik Employees Receive Renowned Raney Award

Dr. Daniel J. Ostgard of Evonik Industries during Vitamin B2 synthesis and the selective hydrogenation of unsat- will receive the renowned Raney Award in urated fatty nitriles to their corresponding unsaturated amines that are recognition of his outstanding work in the used for the production of surfactants and emulsifiers. Ostgard’s field of heterogeneous catalysis. The cata- group has also elucidated the mechanism for the hydrogenating sug- lysis researcher is receiving this award for ars such as fructose and glucose. These reactions produce sugar sub- the development of highly selective stitutes such as sorbitol or mannitol, which are suitable for use by dia- powder and fixed-bed nickel catalysts used betics. Dr. Ostgard has used his catalyst expertise since 2006 in the in industrial hydrogenation processes. The Marketing and Business Development unit of the Catalysts Business Raney Award is given out every two years Line for acquiring new business opportunities. by the Organic Reactions Catalysis Society The ORCS was established in 1975 as a discussion forum for (ORCS) to scientists who have made an im- applied catalysis research, with a focus on organic synthesis. Its mem- portant contribution to catalyst technology bers include both university and industrial researchers from specialty in organic synthesis. Ostgard will accept chemicals, fine chemicals, and pharmaceuticals companies. The or- the award in March 2008 during the ORCS ganization has given out the Raney Award, which is sponsored by the meeting in Richmond, Virginia, USA. “We American company W.R. Grace & Co., since 1992. The name of the are very proud of this honor,” said Dr. Hans-Josef Ritzert, head of award honors the American engineer Murray Raney, who discovered Evonik’s Catalysts Business Line. “It underscores not only the sci- the nickel catalyst named after him in 1926. Raney-type nickel cata- entific quality of our research, but its importance for efficient industrial lysts are commonly used for the transformation of organic compounds systems.” on an industrial scale, especially for the hydrogenation of unsaturated Ostgard has worked for Evonik Industries since 1991 – first in the compounds. United States and then, since 1998, in Germany. One of the primary Evonik is a leading supplier of catalytic system solutions. It offers focuses of his group’s research has been activated metal catalysts. an extensive range of homogeneous and heterogeneous catalysts Some of the group’s accomplishments include catalysts that can be from a single source, as well as an all-inclusive package of services for used for the complete hydrogenation of nitriles to primary amines. customers in the life sciences, fine chemicals, industrial chemicals, Possible applications include the nitrile hydrogenation that occurs chemical intermediates, and polymers segments.

elements21 EVONIK SCIENCE NEWSLETTER 25 TISSUE ENGINEERING Conquering New Territory with

Tissue engineering offers the opportunity of cultivating viable cells of an organism in vitro and replacing damaged tissue, such as skin, with implants made of autologous cells. The generation of complex organic tissue, however, is still in its early stages. Now, researchers at the Fraunhofer Institute for Interfacial Engineering and Biotechnology (IGB) have succeeded in producing an artificial liver. This is not only a precursor of future implants: The laboratory-grown organoid tissues also offer a promising method for testing newly developed active ingredients on human tissue.

Figure 1 Collagen carrier scaffold with conserved tubular structures (vascularized matrix) for the in vitro pro- duction of human tissues filled with the functional equivalent of blood vessels. At the Fraunhofer Institute for Interfacial Engineering and Biotechnology in Stuttgart, this matrix is used as a substrate for endog- enous human cells for the production of artificial tissues and organs

26 elements21 EVONIK SCIENCE NEWSLETTER BIOTECHNOLOGY

Artificial Organs

PROF. DR. HEIKE MERTSCHING

longside stem cell therapy, which has been in use for decades, tissue engineering has recently become an established methodology within regenerative medi- cine. Compared to proven reconstruction of skin and Acartilage, the cultivation of complex organic tissue that depends on blood supply is still in its infancy. Now, with the help of a new process, scientists have succeeded in opening up a new dimen- sion in tissue engineering. To reproduce 3D tissue models with blood vessel supply, re- searchers at the Fraunhofer Institute for Interfacial Engineering and Biotechnology (IGB) used parts of the small intestine of a pig, which they isolated with an artery for the blood supply and a vein for discharge of the bloodstream (s. Fig. 2) by means of a circulating pump. To create an artificial liver from human tissue, all of the ani- mal cells of the pig intestine first had to be removed. To do this, the animal organ was put into a bath, in which the intestinal cells were selectively ruptured by a high osmotic pressure differ- ence. The fragments were removed by rinsing with a chelating agent. This left a collagen matrix, in which the branched net- work of the vascular system was conserved down to the most delicate capillaries (s. Fig. 1). IGB researchers then streamed a nutrient solution enriched with human endothelial cells through this network by means of a circulation pump. In this procedure, the interior sides of the former blood vessels are lined – just like the living model – with the endothelial cells. Signal molecules on the surface of the vas- cular structure ensure adhesion of the cells. The method, which is universally applicable no matter the genus, produces artificial tissue with a functional network of blood vessels that scientists call a 3D vascular tissue model.

A computer controls the vital functions of the artificial liver

This model can now be equipped with the cells of a variety of tis- sues and organs. In addition to the endothelial cells of the artifi- cial bloodstream, IGB researchers introduced hepatocytes into the former intestinal cavity, and within two weeks were able to grow liver-like tissue ex vivo. The artificial blood circulation can keep this tissue “alive” in the bioreactor for weeks. In addition, a computer-controlled envi- ronment was created for the artificial liver that recreated natur- al living conditions as closely as possible. In the human body, hepatocytes are responsible for numer- ous transformations, with the most important of these being Figure 2 Bioreactor with vascularized matrix for in vitro detoxification. Because the liver model and its added hepatocytes generation of complex human tissues. The gener- works, in principle, like a human organ, it opens the opportunity ated tissue is supplied with nutrients and oxygen of studying the toxicity of new active ingredients as well as nano- through an artery, and the metabolites are purged through a vein. The system thus reflects the scale materials. Currently, a trachea model is used to test the ex- smallest unit of human tissue with a functional tent to which nanoparticles are absorbed through the respirato- blood vessel network ry tract organ and circulated in the blood. In subsequent >>>

elements21 EVONIK SCIENCE NEWSLETTER 27 tests, researchers can then explain how these particles are later metabolized in the liver. The artificial liver can even help deter- mine whether long-term effects will occur and what impact an active ingredient will have when it is administered multiple times. Long-term tests for these applications are currently underway at IGB.

Better results without animal testing

The strongest argument for the use of artificial liver in pharma- ceutical research is the fact that it is based on human cells. Such an approach avoids the occasional lack of reproducibility of the results of animal tests. On the other hand, the model also gives us the opportunity to effectively reduce the number of previ- ously unavoidable animal tests. Last, the process is also suitable, in principle, for growing a complete organ for transplantation in the future. Compared to transplants of foreign organs, trans- plants like these, made of endogenous cells, would not be reject- ed by the immune system. This option is still somewhat “pie-in- the-sky” – the time-consuming authorization process alone Figure 3 Bioartificial vascu- would take about five years. larized liver tissue, Without doubt, the test system marks an important milestone produced in the for pharmaceutical research in its ability to identify toxic or in- PC-controlled bioreactor system effective substances in an early phase of the development of ac- (s. Fig. 2) of tive ingredients. Researchers also hope to be able to improve Fraunhofer IGB their understanding of the cell processes responsible for the occurrence of tumors. Additionally, three-dimensional test tissue offers an opportunity to accelerate the development of tumor therapeutics. Chemotherapy is a treatment particularly prone to succeed- ing or failing based on individual differences. To improve con- trol over these individual imponderables, IGB researchers plan to first grow a matrix tumor using tumor cells from patients, then treat the tumor with various chemotherapeutic agents to select the best treatment option for the patient. Other projects planned by the Institute cover all of the hu- man body’s “gateways” for the intake of active ingredients. These include an artificial intestinal model for such studies as the mechanism of drug absorption, also in connection with ad- PROF. DR. HEIKE MERTSCHING vanced drug delivery systems. Another project aims to depict a Biologist Heike Mertsching has been head of the Cell Systems department vascularized full-thickness skin model, which can be used to at the Fraunhofer Institute for Interfacial study the transport of active ingredients from the epidermis to Engineering and Biotechnology in the subcutis. For their part, trachea models should offer insight Stuttgart since 1994. into the absorption of active ingredients through the mucous membrane of the nose and trachea. The findings of these studies could pave the way for development of patient-friendly forms of +49 711 970-4117 drug administration, including nasal sprays and inhalers. ● [email protected]

28 elements21 EVONIK SCIENCE NEWSLETTER BIOTECHNOLOGY

FROM EXTRACTION TO FERMENTATION

New Business Prospects for Specialty Amino Acids

DR. ANDREAS KARAU

At the beginning of 2005, Evonik’s Exclusive of specialty amino acids was limited. With this new fermenta- Synthesis & Catalysts Business Unit made a coura- tion technology, Evonik Industries has now created a future- geous decision: Its French subsidiary Rexim, the oriented platform for operating fast, efficiently, and with sustain- world’s third-largest supplier of pharmaceutical able responsibility in this attractive market. As early as summer Aamino acids, would completely change its production from an 2007, Rexim had successfully validated large-scale fermenta- extractive process based on animal raw materials to fermenta- tive production of two additional amino acids, L-valine and tion. The first work on process development had begun an entire L-isoleucine. Regular production is scheduled to commence in year before that. So after two and a half years in development, early 2008. ● Rexim used the new process to produce its first ten metric tons of the amino acid L-proline in bioreactors in May 2006. The new key technology is now fermentation, in which the desired DR. ANDREAS KARAU amino acids are manufactured from microorganisms. Such Andreas Karau is responsible for research, development, and quality rapid success would not have been possible without the wide assurance at the French subsidiary variety of Evonik units that provided their expertise to assist Rexim located in Ham. Previously, with the conversion, including the Exclusive Synthesis & he headed the ProFerm Project House, which has since concluded its work. Catalysts and Feed Additives Business Units, as well as Creavis and the ProFerm Project House, which has now successfully concluded (s. elements18, p. 12 ff). +33 323 81-4762 Amino acids are a primary component of infusions, are used [email protected] as chiral compounds in the pharmaceutical industry, and are also used in many cosmetic products, as well as in sports and wellness nutrition. Manufacturing processes based on animal raw materials have become controversial in the wake of BSE and other animal diseases. Despite the fact that it is scientifically proven to be safe, acceptance of animal-based starting materials for obtaining pharmaceutical amino acids has dropped. Another important factor is that extraction always involves coproduction, which means that complete participation in the market growth

elements21 EVONIK SCIENCE NEWSLETTER 29 Laying the foundation stone for the new integrated plant in Shanghai. Representing Evonik were Gregor Hetzke (head of Methacrylates, right), Dr. Michael Müller Hennig (2nd from right, head of Specialty Acrylics), Dr. Dahai Yu (3rd from right, Regional President of Evonik Degussa Greater China), Project Manager Dr. Claas Klasen (4th from right),Dr. Manfred Spindler (5th from right, member of the Management Board of Evonik Degussa GmbH), as well as the deputy chairman and chairman, respectively, of Evonik’s Management Board, Dr. Alfred Oberholz (6th from right) and Dr. Klaus Engel (7th from right)

+++ Groundbreaking Ceremony: New Production Plant for Methacrylates in Shanghai

In September, Evonik Industries held the groundbreaking ceremony The integrated production complex will be built on Evonik’s mul- for the newly integrated production plant for the manufacture of tiuser site SCIP, where the Group has been operating a polyester plant methyl methacrylates (MMA) and methacrylate specialties in the and a colorants plant since June 2006, and where a polycondensation Shanghai Chemical Industry Park (SCIP). At a volume of € 250 million, plant for special polymers and a compounding plant will come onstre- the integrated production plant represents the second-largest single am next year. Engel stressed: “China plays a central role for our investment ever made by Evonik’s Chemicals Business Area. “With growth strategy in Asia. Here we must be present on site with our this production plant, we are laying the groundwork for participation production plants. For this reason, we’ll continue expanding our mul- in what is for us a highly attractive growth market. This investment tiuser site in China.” will also consolidate our position as a worldwide leading manufacturer The new production plant for thermoplastic methacrylate resins is of methacrylates,” emphasized Dr. Klaus Engel, member of the Man- scheduled to commence operation in the second half of 2009. The agement Board of Evonik Industries with responsibility for the Chem- plant will be connected downstream of the integrated MMA facility. icals Business Area. “With this plant we’re significantly increasing our worldwide capaci- The world-scale facility is scheduled to come onstream in mid- ties for thermoplastic methacrylate resins,” said Dr. Manfred Spindler, 2009. The integrated MMA production will include, in addition to an member of the managing board of Evonik Degussa GmbH. He also annual capacity of about 100,000 metric tons of MMA, production stated that, in thermoplastic methacrylate resins, the Chinese market plants for methacrylic acid, butyl methacrylate, and PMMA molding has the greatest growth potential worldwide. “And our new plant will compounds. This will mark the creation of a network, unrivaled and put us right in the middle of this market.” unique in the world, for supplying customers in optoelectronics, the paint and adhesives industry, and in automobile manufacture.

+++ PMMA Molding Compounds for Flat Panel Displays: New Plant Comes Onstream in Taiwan

Evonik Industries started up a new production facility for PMMA compounds, with its broad product portfolio for all extrusion and (polymethyl methacrylate) molding compounds in Taichung, Taiwan, injection molding applications. Forhouse, Evonik’s Taiwanese part- together with its joint venture partner Forhouse Corporation. Evonik ner, is one of the leading companies in its field and possesses substan- holds a 51 percent share and Forhouse a 49 percent share in the joint tial expertise in manufacturing and developing lighting modules for venture Degussa Forhouse Optical Polymers Corporation, launched flat panel displays. It operates several production facilities in Taiwan in January 2006. The new plant manufactures high-quality PMMA and China. In 2006, Forhouse generated sales of some € 492 million for optical applications in flat panel displays. with about 6,000 employees. In their joint venture, Evonik and “Global demand for our high-quality PMMA molding com- Forhouse are not only cooperating in their existing business, but are pounds is set to rise significantly in the next few years,” said Gregor also developing new products. Hetzke, president of Evonik’s Methacrylates Business Unit. “The mar- ket for liquid-crystal flat panel displays is currently expanding at an annual rate of more than ten percent. The new production facility Taichung, Taiwan: enables us to serve this growing market from our local site.” Evonik’s new The plant will have an initial annual capacity of some 40,000 production facility for PMMA molding metric tons and is designed for “over-the-fence” production. Apart compounds from PMMA manufacture, the further processing of lighting modules (backlight units) for flat panel displays will also be located at this site. The integrated supply chain ensures the continuous supply of the ultra- high-purity optical-grade material to customers. The PLEXIGLAS® molding compound used to manufacture optical light guides in TFT LCD (thin film transistor liquid crystal display) flat panel displays has to meet the most stringent quality requirements to enable perfect illumi- nation of the displays. The joint venture unites both partners’ core competencies. Evonik Industries is a leading global manufacturer of PMMA molding

30 elements21 EVONIK SCIENCE NEWSLETTER news

+++ Evonik and TSM Plan Construction of an Integrated Solar Silicon Production Facility

Evonik Industries and Netherlands-based The Silicon Mine (TSM) Industries produces its high-purity Siridion® chlorosilanes, which are Sittard-Geleen are planning to build the first integrated production converted by TSM into high-purity solar silicon by means of the well- facility for solar silicon in the Netherlands. For this purpose, the two proven Siemens deposition process: “The synergies of optimized partners recently signed a letter of intent. In this integrated produc- integrated production between the partners Evonik Industries and tion network, Evonik’s Chemicals Business Area will manufacture TSM at one of Europe’s largest chemical sites form the basis for the Siridion® chlorosilanes, from which TSM will produce high-purity success of the project,” explains Dr. Dietmar Wewers, head of solar silicon for the photovoltaics industry. Evonik will invest a high Evonik’s Silanes Business Line. double-digit million euro amount. Creating at least 400 jobs, TSM is planning an annual production “We see solar silicon as a large market with growth over the next of 3,750 metric tons of high-purity solar silicon at the site in Sittard- few years. In the midterm, we aim to take hundreds of millions of eu- Geleen: “That corresponds to five percent of the world market vol- ros in order to massively expand our good position in this attractive ume forecast for 2010,” underlines Gosse Boxhoorn, chairman of the market,” says Dr. Klaus Engel, member of the management board of management board of TSM, adding that annual production capacity Evonik Industries AG and responsible for the Chemicals Business could be increased in the long term even to 14,000 metric tons of solar Area. silicon. The integrated facility is being built at the DSM site in the munici- Evonik Industries is the world’s largest producer of high-purity pality of Sittard-Geleen in the Limburg province, one of the most chlorosilanes. These are raw materials in the production of solar sili- important industrial zones in the Netherlands. At the site, Evonik con, which is itself used to produce solar wafers. The photovoltaics in- dustry then processes these wafers into solar cells and modules. Evonik Industries has been successfully involved in the booming Raw silicon is the starting photovoltaics market for several years. In April this year, Evonik con- material for Evonik’s cluded an agreement with the French company Silicium de Provence ® Siridion chlorsilanes, (Silpro) for a similar integrated production of 4,000 metric tons per from which TSM produces ultra-pure solar silicon for year of solar silicon. The following month it signed jointly with PV the photovoltaics industry Silicon, Erfurt, a long-term supply agreement to provide the 1,800- metric-ton solar silicon production facility currently under construction in Bitterfeld with Siridion® chlorosilanes. As early as 2002, the company established, with SolarWorld AG of Bonn, the joint venture Joint Solar Silicon GmbH & Co. KG head- quartered in Freiberg, Saxony. It will produce 850 metric tons per year of solar silicon from monosilane at Evonik’s Rheinfelden site.

+++ R&D Center Expanded in Shanghai

For more than € 10 million, Evonik Industries has enlarged its “Our enlarged R&D center will help us strengthen the interface research and development (R&D) center in Shanghai. As one of the between the various business units and customers, universities, and largest R&D centers ever established by a multinational company in research institutes in China and provide customers with tailor-made Shanghai, the new R&D center has a total of 25,000 square meters of solutions and our high-quality products. Our center will also be the space, housing state-of-the-art laboratories for research and develop- headquarters for our marketing and sales activities in China, as well as ment, application technology, and technical service. The investment the principle site for Evonik’s Chemicals Business Area in this region,” included the construction of a pilot facility for polymer engineering in said Dr. Dahai Yu, regional president of Evonik Degussa Greater China. a four-story building with a footprint of 1,250 square meters. “The expansion of our R&D center marks yet another milestone for The former Shanghai R&D center, in which Evonik invested € 12 our China efforts. We expect sales in the Greater China Region to reach million, was inaugurated in April 2004. The expansion provides, € 1 billion by 2009.” In the years to come, and in its Chemicals Busi- among other things, a regional hub for sales, marketing, technical ness Area, Evonik plans to invest some € 100 million annually in China services, R&D, and the service platform for customers in China and alone, thereby underscoring its firm commitment in this growth region other countries in the Asia-Pacific region. even further.

elements21 EVONIK SCIENCE NEWSLETTER 31 NANOEMULSIONS FOR PEG-FREE COSMETICS ...... by Simple Dilution

A new emulsion technology from Evonik’s Care & Surface Specialties Business Unit allows easy manufacturing and processing of low-viscosity oil-in-water nanoemulsions that are free from emulsifiers based on polyethylene glycol (PEG). Such blends are highly attractive for the growing market for impregnating emulsions for moisturized tissue. Evonik scientists have transferred the advantage of easy processing to classic emulsions.

32 elements21 EVONIK SCIENCE NEWSLETTER INTERFACIAL TECHNOLOGIES with Water

DR. JÜRGEN MEYER

il-in-water emulsions (O/W emulsions) play an The conventional process for manufacturing finely dis- important role in cosmetics: They are fundamental persed O/W emulsions with a transitional phase inversion is the to the formulation of such products as body lotions, PIT method (Phase Inversion Temperature method), in which skin creams, and sunscreens. Another relatively the phase transition is obtained by cooling. O/W nanoemulsions Orecent but fast-growing field of application is emulsion-based manufactured by this method are long-term stable and are used wet wipes for such applications as baby care and make-up for a number of cosmetic applications (e.g. wet wipes, sprayable removal. The key components in these products are low-visco- emulsions). PIT emulsions utilize the temperature-dependent sity O/W emulsions with good storage stability. Classic emul- hydrophilicity of the ethoxylated emulsifiers. sions have typical particle radii of between 0.5 and 10 micrometers which causes their typical white With the PIT method, the phase inversion temperature method, the affinity of the emulsifier appearance, and usually show viscosities of over for the two phases changes at the oil and water interface, depending on the temperature. 1,000 mPas. They are kinetically stable, and can be When a W/O emulsion is cooled, a transitional phase inversion occurs that results in low- manufactured with the help of a homogenizer. Be- viscosity, finely-dispersed O/W nanoemulsions with good storage stability cause their particles are relatively large, however, comparable low-viscosity systems are unstable and cream up. T [ºC] Alternatively, O/W microemulsions are easy to produce because of their thermodynamic sta- 80 ºC φ W/O μE region bility. They are translucent, and their typical parti- 2 emulsions cle radii range between ten and 40 nanometers.

Microemulsions form spontaneously upon mixing, PIT 1φ and the order in which the components are added 3φ

makes no difference. However, microemulsion for- 2φ mation usually requires large quantities of emulsi- O/W emulsions fiers and surfactants. RT In terms of their properties, nanoemulsions are PIT emulsion positioned between microemulsions and traditio- (kinetically stable nanoemulsion) nal emulsions. Their typical particle radii range between 30 and 100 nanometers which causes Concentration emulsifiers their typical blue-shining appearance. At these small particle sizes, the Brownian motion prevents creaming, and as a result nanoemulsions often have a long-term good stability. Like classic emul- sions, nanoemulsions are kinetically stable. They are typically Wanted: PEG-free alternatives to PIT emulsions not easy to produce as they require either high-pressure homo- genizers or very specific manufacturing processes. The use of ethoxylated emulsifiers, however, is seen more and The scientists from Evonik’s Care & Surface Specialties more as a disadvantage. Because consumers increasingly prefer Business Unit have now overcome this disadvantage with the natural ingredients in cosmetics, the industry is extremely in- development of a low-energy emulsion process for the manu- terested in PEG-free emulsions. And this is just what Evonik has facturing of nanoemulsions. In this process, a phase with extreme- now made possible: the manufacture of nanoemulsions without ly low surface tension is passed. In this phase, the transitional homogenizers, without energy input for heating/cooling steps, phase inversion occurs as the affinity of the emulsifier towards and without ethoxylates. An oil phase based on this new technol- the oil and water phase changes continuously. To put it in graphic ogy platform typically consists of three components: PEG-free terms, the curvature of the surface changes from W/O (concave) emulsifiers (ten to 30 percent), cosmetic oils (50 to 90 percent), to O/W (convex) in this process. As it changes, the emulsion and cosurfactants (one to 20 percent). Cosurfactants are surface- goes through a microemulsion-like phase in which the surface is active. However, unlike surfactants, they do not form micelles not curved. in water, and therefore do not tend to self-aggregate. >>>

elements21 EVONIK SCIENCE NEWSLETTER 33 Phase behavior of the TEGO® Wipe DE system, depending on the water content, at 20 °C (68 °F). At a water content between 35 and 70 percent, the phase transition from a W/O emulsion to an O/W emulsion occurs. The pronounced viscosity minimum indicates that a phase with extremely low interfacial tension is passed ■■ Conductivity ■■ Viscosity Conductivity [μS/cm] Viscosity [mPas] 600 120 550 Clear W/O Microemulsion- 0/W 500 solution emulsion like phase emulsion 100 450 400 80 350 Simple manufacture of nanoemulsions – for example, for moisturized tissues: Add water to the clear oil phase of the TEGO® 300 60 Wipe DE system (left), and following a microemulsion-like phase 250 (middle), a low-viscosity O/W nanoemulsion with long-term 200 40 stability forms (right) 150 100 20 50 0 0 sume that the water-solubility of the phenoxyethanol 02040 60 80 100 is decisive for the occurrence of a microemulsion-

Bicontinous structure Weight % H2O like phase: With increasing water concentration, the cosurfactant increasingly migrates out of the surface

The role of the cosurfactant in PIC emulsions: The solubility of the cosurfactant presumably film and into the water phase, which assists the phase ensures that, with increasing water concentration, the cosurfactant increasingly migrates from inversion. The phase inversion is also promoted by a the surface film into the aqueous phase, thereby assisting the phase inversion co-emulsifier, such as dilauryl citrate, that becomes more hydrophilic with increasing water concentra- tion. Following the successful development of such O/W nanoemulsions, Evonik’s scientists wondered what they could transfer to the formulation of classic emulsions. In the end, they were able to develop PEG- free emulsifier that requires no heating or homog- enizer. For this emulsifier they used a mixture of polyglyceryl-4-laurate and dilauryl citrate, which If water is added to this kind of liquid and clear oil phase, a had been developed for PIC emulsion systems and has self- microemulsion-like phase is passed and a low-viscosity O/W emulsifying properties. This mixture is pasty, however, and too nanoemulsion with good long-term stability is obtained. The expensive for typical applications. Consequently, they combined first of Evonik’s products based on this technology are TEGO® this highly active mixture with the liquid basic emulsifier sorbi- Wipe DE and TEGO® Wipe DE PF, which are for the simple man- tan laurate. Marketed as TEGO® Care LTP, this new O/W emul- ufacturing of impregnating emulsions for cosmetic wet wipes. sifier mixture can be cold-processed, and allows simple and cost- In their tests, Evonik’s scientists were able to determine that effective production of cosmetic products in the form of sprays, the viscosity of the TEGO® Wipe DE system depends heavily on lotions, and creams. ● the water content. In the microemulsion-like phase, there is a significant reduction in viscosity, which indicates extremely low interfacial tension at this point. Similar to the PIT emulsion system, this kind of minimum viscosity is typical for the point of phase inversion from W/O to O/W. Because this inversion DR. JÜRGEN MEYER point occurs at a certain water concentration, the Care & Surface In Evonik’s Care & Surface Specialties Specialties Business Unit calls the new process a phase inversion Business Unit, Jürgen Meyer is re- sponsible for the application technology concentration technology. These PIC emulsion systems require laboratory in the Personal Care Leave- no stirring or heating. Even the order in which the oil and water On unit, which focuses on products that are added has no impact on the result. The emulsion mixture stay on the skin. Most of his work in- volves the development of new raw and cosurfactant content, however, must be precisely adjusted materials, such as emulsifiers and emol- with the oil phase to be emulsified. lients (cosmetic oils), development of In the TEGO® Wipe DE system, the surface-active phenoxy- new formulation ideas for cosmetic leave-on applications, and management ethanol, which is often used as a preservative in the cosmetics of customer-related projects. industry, plays the role of the cosurfactant. The researchers as- +49 201 173-1621, [email protected]

34 elements21 EVONIK SCIENCE NEWSLETTER INTERFACIAL TECHNOLOGIES

Water Makes the Diesel Clean Microemulsions Reduce the Discharge of Pollutants from Engines

Aqueous diesel microemulsions can drastically reduce not only the soot particles but also nitrogen oxides that are generated during combustion. Chemists at the University of Cologne have successfully manufactured these blends and proven their suitability for everyday use in tests.

PROF. DR. REINHARD STREY

cientists have been experimenting with emulsions for interface changes from convex to concave when the temperature improving fuel combustion since the 1970s and 1980s. increases. With ionic surfactants, the interface behavior is pre- These classic emulsions proved problematic, however, cisely the opposite. because of their thermodynamic instability and ten- For this reason, the phase behavior of a microemulsion can Sdency to separate. In addition, the water-oil ratio is not easy to be adjusted through the temperature and the mass portion of increase after the emulsion is created. Microemulsions, whose surfactant relative to the total system. Phenomenologically, the thermodynamic condition regulates spontaneously, offer a way mechanisms this is based on are understood and reproducible. out of this dilemma. The typical microemulsion has a particle Theoretically, they still await a complete explanation. A micro- size of between one and 100 nanometers. Microemulsions react emulsion becomes temperature-invariant when suitable ionic flexibly to the addition of water or oil. and non-ionic surfactants are mixed in such a way that the inter- Microemulsions are thermodynamically stable mixtures of face curve of the system remains constant. oil, surfactants, and water. The surfactants form the interface Phase diagrams are useful for describing the behavior of between water and oil, because their hydrophilic portion – the microemulsions. According to the diagram, there are areas for a head – and their hydrophobic portion – the tail – want to point certain oil-water system in which two phases develop (oil over toward the water and the oil, respectively, but need different water-surfactant, or oil-surfactant over water), and there is an amounts of space. With non-ionic surfactants, whose heads con- area in which three phases (water, microemulsion, oil) occur. sist primarily of ethylene glycol units or sugars, the water-oil For each microemulsion, there is an optimal point at which >>>

elements21 EVONIK SCIENCE NEWSLETTER 35 Figure 1 Structure in microemulsions: The structure of the interface between water and oil is influenced by the differing space needs of the heads and tails

Non-ionic surfactant Cold Hot

Water Water Water

Oil Oil Oil

Hot Cold Ionic surfactant

only one phase forms: the X or fishtail point. Here, the micro- emulsion shows a bicontinual structure, which is also called the Figure 2 Phase behavior of a microemulsion system that contains the same amount sponge structure. Here, the minimal amount of surfactant is of oil and water, depending on the temperature and surfactant content γ. required and the size of the interface between water and oil is An optimal microemulsion forms at the X or fishtail point: It consists of only minimal and locally planar. one phase and is characterized by a bicontinual, sponge-like structure

Diesel engines: putting carbon dioxide and nitrogen oxide emissions to the test Water in oil At the University of Cologne, scientists have experimented for – years with these kinds of diesel-and-water microemulsions with 2 the aim of drastically reducing the environmental damage caused by today’s engines. Soot is an unwanted result of today’s diesel engines and must be removed with expensive particle filters, T which actually increase fuel consumption. So while these filters 3 Lα do lower soot emissions, they actually cause an increase in the emission of nitrogen oxides. With a series of measurements at TÜV Essen in conformance with the European Union End-of-Life Vehicle Directive, as well 2 – as at the Technical University of Trier, the researchers from Cologne proved that the emissions of vehicle engines that were Oil in water driven with a water-diesel microemulsion dropped dramatical- ly: the discharge of soot particles by 70 to 90 percent, and of ni- trogen oxides by 30 to 60 percent. In these tests, the researchers φ=0,5 also experimented with various mixtures that were up to 45 per- γ cent water. The reason for lower emissions as compared to pure diesel is that the bicontinual structures of microemulsion presumably cause a more even combustion after the injection of fuel. With traditional diesel injection, the soot primarily occurs through PROF. DR. REINHARD STREY Prof. Strey has been a C4 professor for physical the relatively slow diffusion of the atmospheric oxygen to the chemistry at the University of Cologne since 1996. fuel droplets in the combustion chamber. Additionally, free oxy- His R&D activities include boundary layers, colloids, gen and hydroxy radicals of the water, which are dissociated at and phase changes. Of special interest within these areas are nanostructure, the thermodynamics and the high temperatures, reduce the soot. kinetics of liquids, especially of microemulsions, Less nitrogen oxide occurs, in turn, because the high evapo- and their use in aqueous fuels, as well as a template ration enthalpy of the water lowers the combustion temperature. for nanofoams.

At the same time, however, the evaporation of the water increases +49 221 470-4458, [email protected] the gas pressure, so that the engine can perform at the same strey.pc.uni-koeln.de

36 elements21 EVONIK SCIENCE NEWSLETTER INTERFACIAL TECHNOLOGIES

■■ ■■ ■■ ■■ ■■ ■■ Diesel ME: 9 % H2O ME: 18 % H2O ME: 27 % H2O ME: 36 % H2O ME: 45 % H2O

Figure 3 Soot emissions at n=1,500 min –1 Soot emissions at n=2,100 min –1 Reducing soot emissions: The FSN FSN FSN (Filter Smoke Number) was used 1.4 1.4 to measure the soot discharge, depending on the load and the 1.2 1.2 engine speed n. The diagram shows the characteristic lines for microemulsions with various water 1.0 1.0 content and at constant engine speeds. At all performance levels, 0.8 0.8 the soot emissions are reduced with increasing water content. At 0.6 0.6 water content from 27 percent, the combustion proved to be nearly free from soot with a reduction 0.4 0.4 of over 90 percent 0.2 0.2

0 0 0 50 100 150 200 250 300 350 0 50 100 150 200 250 300 350 Load [Nm] Load [Nm]

–1 –1 Figure 4 NOX emissions at n=1,500 min NOX emissions at n=2,100 min Reduction of nitrogen oxide emis- sions: The diagram shows the highly 1.400 1.400 load-dependent emissions of NOx for two constant engine speeds. 1.200 1.200 With increasing water content, the emissions of microemulsion drop continuously, while the presence 1.000 1.000 of small loads results in a higher percentage reduction. Higher water 0.800 0.800 content leads to only minimal changes 0.600 0.600

0.400 0.400

0.200 0.200

0 0 0 50 100 150 200 250 300 350 0 50 100 150 200 250 300 350 Load [Nm] Load [Nm]

level despite the lower temperature. When the temperature Depending on the application, the microemulsion must not drops, the heat flow also drops proportionately – and with it the be premixed, but rather mixed immediately prior to use. The heat loss of the engine. The result is up to 20 percent greater ef- Skarabäus company, for example, which has developed a pro- ficiency. Since these tests, the scientists have now patented their cess-controlled emulsifying system for an automobile, is exper- water-diesel microemulsion (DE 103 34 897.2). imenting with this “onboard mixing,” which can dose the water content depending on the load. Interesting fields of application: One of the next goals for the scientists from Cologne is mea- block thermoelectric power plants and ships suring the emission behavior of engines in day-to-day operation. In the future, they also want to lower the share of surfactant Car and truck engines are not the only conceivable application. needed for the microemulsion to below ten percent. Additional Long-term tests are planned for block thermoelectric power plans include improving the temperature stability. Currently, plants, and the fuel could also be attractive for buses and ships. microemulsions are stable between zero and 95 °C (32 and Eighty percent of soot emissions in the Port of Hamburg, for ex- 203 °F). In any case, because of its thermodynamic properties, ample, come from anchored ships whose engines run only for the water-diesel mixture has no problem with long-term stability: the sake of generating onboard electricity. It easily achieved values similar to conventional fuels. ●

elements21 EVONIK SCIENCE NEWSLETTER 37 EVONIK IS THE LEADING PRODUCER OF INORGANIC PARTICLES Nearly Endless Applica

Inorganic particles are indispensable for a great many applications. They can be found in rubber compounds, coatings, adhesives, sealants, and plastics, as well as in cosmetics and catalysts. Thanks to its expertise in customized production of these particles, Evonik is a preferred partner for a host of different industries.

The processing of paper (left) to inexpensive high-gloss photo paper (right) is only one of the many application possibilities for customized inorganic particles from Evonik’s Aerosil & Silanes Business Unit

DR. PETER NAGLER

norganic particles are all around us – perhaps their most beautiful form is the long, white beaches that invite us to Designing inorganic particles involves the selective control of key characteristics, such as the size of the primary particles, the swim and relax. Yet not for tourism, but for many industrial size and form of the aggregates, as well as the surface chemistry applications inorganic particles are becoming more and more Iimportant. They play an increasingly significant role in nano- technology, for example. The DG Bank predicts that by the year 2010, inorganic nanomaterials will account for as much as 28 percent of total sales in nanotechnology. This corresponds to Primary particle size over € 60 billion and an enormous € 12 billion in growth since 2001 (the market share then was 23 percent). Evonik’s Chem- Aggregate size icals Business Area has a considerable stake in this market. Cur- Aggregate shape rently, the company produces roughly 1.7 million metric tons of inorganic particles per year, and generates sales of about € 1.8 Surface chemistry billion. This makes it one of the world’s leading manufacturers. The product portfolio includes carbon blacks, precipitated and fumed silicas, and an array of fumed oxides, such as aluminum oxide and titanium oxide, as well as a variety of mixed oxides. Production takes place at 36 sites in 18 countries worldwide. When particles are created in a flame reaction, the smallest Inorganic, nanostructured particles can be customized primary particles form first, which then grow into larger particles through precise control of key characteristics, first and fore- in the hot zone and, later, into aggregates. By colliding, these most of which includes the size of the primary particles and the aggregates form even larger agglomerates in the cooler zone of aggregates they create, their form as well as surface chemistry the reactor — and all this occurs in the first 100 milliseconds. (the particles have a high specific surface of up to 1,000 square The reactor selection and manufacturing conditions alone can meters per gram). There are various methods for producing generate different particles, as we can see from the example of nanoparticles – including different liquid and gas-phase syn- carbon black. The gas black process, for example, can adjust pri- theses, as well as milling processes. Precipitation processes and mary particles to between about 10 and 30 nm in size. With fur- flame reactions are used predominantly at Evonik. nace carbon black, particles are controllable to between approx-

38 elements21 EVONIK SCIENCE NEWSLETTER INORGANIC PARTICLE DESIGN tions

imately ten and 80 nm, and with lamp black, between 90 and Evonik’s newly developed dynamic gas-phase 100 nm. These carbon blacks also differ in terms of their struc- process for producing inorganic particles allows a narrow ture – that is, how the aggregates branch – because the primary particle-size distribution with low aggregation particles are not isolated, as the above diagram shows. For flame hydrolysis of metal halides, Evonik has also developed a process Hot gas supply that allows the production of a great variety of metal oxides. Precursor One variable that can be used to create different particles in this Injector Particle formation and growth Water supply process is the dwell time in the reaction zone. The rule of thumb: The longer the dwell time, the larger the aggregates.

New process for particle synthesis Quenching First nozzle Reaction volume Second Completely new reaction pathways are opened when gas dynam- nozzle ics are introduced to particle synthesis – a method that Evonik and its seven university partners, as well as the German Aero- space Center, are developing and testing as part of a project sponsored by the German Research Foundation (DFG). The es- sential equipment for this process is two gas jet systems for ul- file in the reactor. In this way, particle diameters can be selec- trafast heating and cooling of the reaction gases. The reactor is tively controlled to produce a narrow particle-size distribution. supplied with pressurized hot gas. The mixture of base material Against the backdrop of these synthetic options, Evonik’s and combustible gas is homogeneously ignited behind the first Chemicals Business Area has an exceptionally wide variety of jet by an ultrasonic burst. Particle genesis and growth then fol- inorganic particles that create new functionalities in completely lows. With the same effect, the particle formation is interrupted different areas of application. The list of fields is nearly endless: at the second jet, and the gas is quenched with cold water. This ar- They range from the rubber industry with the main application rangement promises several advantages: One is that the process in tires, through sealants and adhesives, paints and coatings, allows very high heating and cooling rates. Another is that it printing inks, ink jet pigments, paper, plastics, cables, fibers, enables high throughput and a homogeneous temperature pro- illuminants, plant protection formulations, defoamers, and >>>

elements21 EVONIK SCIENCE NEWSLETTER 39 catalysts, all the way to animal feeds, cosmetics, and toothpastes. The product INDISPRON® D 110, which contains a modified In car tires, for example, carbon black and silica are used to im- silica, is opening up a completely new application. It has long prove abrasion resistance, wet grip, and rolling resistance, while been known that silicas have a drying effect on insects. Because in other applications they have a positive impact on elasticity, they are easy to apply as an aqueous dispersion, they offer a simple stability, rheology, and conductivity, or impart water re- and highly effective opportunity to fight such widespread para- pellency, transparency, and dispersibility – to name just a few. sites as the red fowl mite in layer hen husbandry. Suitable spray Custom-tailored particles like the new Aerosil® type R 9200, equipment is used to apply the milky, yoghurt-like liquid to all a surface and structure-modified fumed silica, have significantly surfaces of the housing – a method that has great advantages improved the scratch resistance of automotive paints. The inor- over powders in terms of dosing, adhesion and occupational ganic particles are homogeneously distributed in the surface of safety. The registration to use INDISPRON® as an insecticide is the paint and, thanks to their hardness, improve resistance to ongoing in a number of countries. In Germany, where about 18 mechanical stresses such as car wash brushes and tree branches. billion eggs are consumed annually, it has been registered since New inorganic particles also make the difference between black July. Evonik promotes its new product with the slogan “Safe food and black in the painting of vehicles – the innovative furnace from the stable to the table.” black pigments with a bluish tinge can be dispersed extremely The potential uses of inorganic particles are nearly unlim- well, are exceptionally weather resistant, and thus are particular- ited: zinc oxide for UV protection; indium tin oxide for trans- ly well-equipped to meet the needs of the automotive industry. parent and antistatic coatings or for IR absorption; Zirconia for technical ceramics and wear protection; and MagSilica®, an iron No high-performance chips without polishing slurries oxide in a matrix made of fumed silicas for resolvable adhesive bonds. Adhesives that contain MagSilica® can be warmed through Microchips are becoming increasingly smaller and more com- a magnetic alternating field, and thereby harden far faster than plex. A vital requirement for the structures, which are now part conventional products. They can also be redissolved, however, of the nanocosmos, is chemical-mechanical planarization through precise heating, which effectively “switches off” the (CMP). This process must be applied several times per wafer, and adhesive bond. involves the use of slurries made of ceroxide (AdNano® Ceria), Thanks to its expertise in the customized production of silicone oxide (Aerosil® 90) and aluminum oxide (Aeroxide® these particles, Evonik is a preferred partner for a whole host of ALU C) for various conducting and insulating layers. Studies different industries. The company also has an excellent basis for have shown that when polishing liquids are not optimized, de- expanding its “particle zoo,” if needed. ● fect rates resulting from such factors as residual ceroxide on the processing surface are high, and can be reliably avoided by using Evonik’s product.

Electron micrograph of a surface that was polished with a non-optimized (photo left) and an optimized polishing liquid based on AdNano® Ceria (photo right)

Aerosil® R 9200, a new surface and structure-modified fumed silica, makes DR. PETER NAGLER automotive paints considerably more scratchproof (photo right) and more Peter Nagler is head of Research, resistant to mechanical stresses such as those encountered in a car wash. Development, and Application These properties are based on the homogeneous distribution of inorganic Engineering in Evonik’s Aerosil & Silanes particles in the surface of the paint (photo below) Business Unit.

+49 6181 59-3562 [email protected]

40 elements21 EVONIK SCIENCE NEWSLETTER INORGANIC PARTICLE DESIGN

INORGANIC NANOFILLERS FOR TRANSPARENT POLYMERS

Invisible Helpers for New Functionalities

PROF. DR. STEFAN KASKEL

norganic fillers have been used in polymers for decades, espe- gregates and agglomerates – offer great opportunities. A particle cially for improving their mechanical behavior. But different size of below 40 to 50 nm is essential for manufacturing trans- fillers can also positively influence UV and fire resistance, parent nanocomposites. The scatter light intensity also increases electrical conductivity, and thermal stability. Nowadays, more significantly with the growth in particle size. Displays, light di- Iand more fillers also contain nanoparticles to add more function- odes, and illumination are the primary application opportuni- ality to matrix plastics or to further improve their properties. ties for luminescent nanoparticles and the luminescent nano- While traditional composites with particles in the microme- composite materials derived from them. Methods for supplying ter range or agglomerates scatter light and thereby do not lend inorganic nanoparticles and their dispersion in polymers have themselves to optical applications because of their turbidity, been developed at the Institute for Inorganic Chemistry at the nanoparticles below 100 nanometers (nm) are so small that they Technical University of Dresden. impart high transparency. In addition to extreme hardness and One option is to use microemulsions, which are thermody- thermal stability, inorganic particles also give the polymer spe- namically stable compounds of water, oil, and surfactants – cial electrical and optical properties. water-in-oil emulsions – in which the size of the water droplets To produce such materials, scientists need special synthetic and, therefore, that of the particles, is controllable over a wide pathways not only to create nanoscale particles but to distribute range through the surfactant content. them as aggregate-free and homogeneously in the polymer as In a study in Dresden, the method was applied to the manu- possible. Processes that produce the particles as far as possible facture of composites with bismuth oxide particles as a reddish- in situ, and integrate them as such into the polymer – while at brown color pigment. BiOI particles are formed when two the same time preventing them from clustering into larger ag- emulsions containing bismuth oxide and iodide ions are >>>

BaTiO3 nanoparticles

Stabilization of the BaTiO3 structure by carboxylic acid (schematic)

O M R – C O

elements21 EVONIK SCIENCE NEWSLETTER 41 mixed together. If the oil phase is replaced by a reactive mono- can be added to achieve a phase transfer to pentane or heptane, mer, the entire compound can be polymerized. In this process, and the monomer can be incorporated into this stable phase. the BiOI particles are distributed into the matrix as separate In the actual study, the doped yttrium vanadate was photo- nanoparticles, which results in a highly transparent material. polymerized with lauryl acrylate. Examination of the particle The color can be programmed from light yellow to reddish- size distribution in the water and in the polymer showed nearly brown, depending on the particle size. The method is limited identical values, which provided evidence that there was no primarily because it realizes a low solids content of no more aggregation. A larger solids content of up to ten percent can be than two percent. The manufactured composites show a photo- reached with this method, although higher contents will pro- chromatic effect – in other words, UV light can be used to tune gressively impair transparency. The method can be used to pro- the color from yellow to brown and back again. duce invisible samples, for example, or characteristics that can be seen only under a UV lamp and, therefore, heighten security Homogeneous distribution of nanoparticles against brand piracy. through phase transfer Monomer coordination also offers an opportunity to create nanocomposites. In one example, zinc acetate dihydrate was A second process is phase transfer. Europium-doped yttrium dispersed in ethanol, and was then replaced by polybutanediol vanadate is an efficient red illuminant used in such products as monoacrylate (PBDMA). Control over the size of the ZnO parti- color TVs and displays. Europium is the source of luminescence cles is possible at the time BDMA is added to the ethanol-based within the yttrium host lattice. Nanoparticles of this compound ZnO dispersion. The process has achieved up to eight weight can be dispersed in water and stabilized with citrate. Amines percentages of ZnO in the polymer, while preserving high

BiOI nanoparticles Patterning ZnO/BDMA composite Transmission Electron Microscope Luminescent pattern Distribution of ZnO nanoparticles in the polymer in YVO4: Eu nanocomposites (Transmission Electron Microscopy)

Photchromatic pattern generation in BiOI nanocomposites

42 elements21 EVONIK SCIENCE NEWSLETTER INORGANIC PARTICLE DESIGN

transparency. The ZnO dispersion in BDMA can be polymer- secondary electron-scanning microscope (SEM), which were ized directly by UV radiation or heat input. Cross-sectional stud- prepared for barium as well as for titanium, reveal the extreme- ies using a transmission electron microscope (TEM) show very ly fine dispersion of barium titanate particles in the polymer. good distribution of the particles in the polymer. After incorpo- The mean value of the particles is 3.6 nm, at a close size distri- ration of the nanoparticles, the mechanical properties, such as bution of only a few nm more or less. the elasticity module, are significantly improved. Even the Integration of inorganic nanoparticles into polymers allows embrittlement properties of the matrix plastic are optimized by the properties of both classes of materials to be combined. The the ZnO particles, thanks to the UV protection. advantages are mainly twofold: new functionalities and new Ferroelectric ceramics are used as fillers for the design of di- processing methods. In principle, we have a wide selection of in- electrical components. A typical example is barium titanate, organic components, as well as polymer matrices, from which to which is incorporated into non-conducting polymers. A fourth choose. Producing these materials when higher particle content process, two-phase hydrothermal growth, is used for this appli- is required, however, remains a challenge. Thus far, the work cation. First, barium and titanate are dispersed as salts of oleic done in Dresden has fallen under the category of basic research. acid in the oil phase. With caustic soda solution as the mineraliz- It would be interesting if the research could now turn toward er, crystallization occurs at the oil-water interface: The barium applications, such as electroluminescent components. The opti- titanate changes the phase under heat input and is present in cal, magnetic, and electric properties are so highly promising nanocrystalline form in the oil phase, while sodium oleate forms that further effort would surely prove rewarding. ● in the aqueous phase. Polymerization – with polylauryl acrylate, for example – is obtained from the oil phase. Images from a

PROF. DR. STEFAN KASKEL Stefan Kaskel has been Professor for Inorganic Chemistry at the Technical University of Dresden since 2004. Previously, he worked at the Max Planck Institute for Coal Research in Mülheim an der Ruhr. His areas of research are the design, synthesis, characterization, and applications of porous and nanostructured materials with an emphasis on metal organic frameworks (MOF), mesoporous materials, and polymer nanocomposites. +49 351 4633-4885, [email protected]

elements21 EVONIK SCIENCE NEWSLETTER 43 events

DECEMBER 07

12/03–12/07/2007 12/16–12/21/2007 17th International Photovoltaic Science International Symposium on and Engineering Conference Catalysis & Fine Chemicals FUKUOKA, JAPAN SINGAPORE www.pvsec17.jp www.cfc2007.org/index.html

JANUARY/FEBRUARY 08

01/09–01/10/2008 02/17–02/19/2008 02/21–02/22/2008 02/27–02/29/2008 6th European Industrial Utilization of 2nd International Symposium 41st Annual Meeting of Motor Biofuels Forum Renewable Raw Materials on Biothermodynamics German Catalysis Experts ROTTERDAM, THE NETHERLANDS FRANKFURT, GERMANY FRANKFURT, GERMANY WEIMAR, GERMANY www.biofuels2008.eu events.dechema.de/Tagungen/ events.dechema.de/Tagungen/ events.dechema.de/Tagungen/41_ Industrielle+Nutzung+nachwachsender+ Biothermodynamics+2008.html +Jahrestreffen+Deutscher+Katalytiker. Rohstoffe+_+Chemie_+Biotechnologie_ html +Verfahrenstechnik.html

APRIL/MAY 08

04/12–04/18/2008 05/18–05/21/2008 EUCHEM Conference on Rolduc Polymer Meeting 2008 Stereochemistry KERKRADE, THE NETHERLANDS BÜRGENSTOCK, SWITZERLAND www.rolducpolmeeting.org www.stereochemistry- buergenstock.ch/

JUNE/JULY 08

06/03–06/05/2008 07/20–07/24/2008 07/28–08/01/2008 American Coatings Show 48th Symposium on Polymer Colloids XXII IUPAC Symposium on CHARLOTTE, NORTH CAROLINA, USA PRAG, CZECH REPUBLIC Photochemistry www.american-coatings-show.com/ www.imc.cas.cz/sympo/48micros/ GOTHENBURG, SWEDEN photoscience.la.asu.edu/Goteborg2008/

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