An Introduction to Polyelectrolyte Multilayers
Layer-by-Layer Adsorption (LbL):
An Enabling Technology for the Nano- construction of Multifunctional Films on Solvent Accessible Surfaces.
G. Decher / Institut Charles Sadron Institut Charles Sadron 1 Differences between chemistry in bulk and at interfaces
Some trivia:
• Surface functional groups accessible only from the solution side.
( SN1 might be favored over SN2 ; reactivities different from bulk) • Typical monolayer thicknesses of 0.5 nm to 5 nm. • Typical surface areas of 0.20 nm2 per molecule, 5 1014 molecules per cm2. • At a mass of 400 g/mol, 1 cm2 of a densely packed monolayer corresponds to 0.33 µg of material. • 5g (semi-preparative scale), would cover an area of 1500 m2. • Monomolecular layers of polymer may be thinner and less dense and typically consist of 0.1 to 1.5 mg of material per 1 m2. • Less than 0.02 mg for chemical analysis and physical characterization
Advantage: We only need tiny amounts from colleagues doing synthesis
Institut Charles Sadron 4 Build-to-Order Assembled Films
Build-to-Order (BTO) is the capability to quickly build standard or mass-customized products upon receipt of spontaneous orders without forecasts.
Layer-by-Layer assembly allows to design functional surfaces and surface-based nano-devices in a "build-to-order" fashion. It exceeds simple self-organization under equilibrium conditions by making it possible to arrange many different materials at will with nanoscale precision.
Institut Charles Sadron 5 The multilayer films that can do everything . . .
Pierre Schaaf, Gero Decher, Jean-Claude Voegel La Recherche, No. 389, SEPT. 2005, 56-58
Institut Charles Sadron 6 A Disruptive Nano-Coating Technology
Layer-by-layer deposition can provide solutions in two areas:
• Surface modification (engineering the interaction of a given object with its environment) • Fabrication of thin film devices (permitting multimaterial assemblies including proteins and colloids) Applications: anticorrosion, antireflective coatings, biocompatibilisation, biosensors, implants, optical waveguides, electroluminescent devices, microreactors, and many more …
The ease by which even multimaterial coatings can be put together using an environmentally friendly low cost technique has kindled widespread interest, not only in academia. The first commercial products have already been introduced to the market in 2001, 2002 and 2004.
Institut Charles Sadron 7 Schematic of the Layer-by-Layer Deposition Process
Simplified “molecular” picture of the first two adsorption steps depicting film deposition as starting with a positively charged substrate. Counterions are omitted for clarity. Polyion conformation is highly idealized and layer interpenetration is not shown in order to better represent the surface charge reversal with each adsorption step.
G. Decher, Science 277, 1232-1237 (1997) > 1750 ISI-Citations (as of January 2006)
Institut Charles Sadron 8 LbL is (analogous to) a chemical reaction !
Classic Synthesis LbL - Deposition
Reagent(s) Surface (atoms, synthons) (template) series of series of reaction deposi- steps tion steps
Product(s) Multilayer Film (typically single species) (defined layer sequence)
Molecular scale Nano (meso) scale
Multilayer Thin Films: Sequential Assembly of Nanocomposite Materials; Decher, G. and Schlenoff, J. B., eds., Wiley-VCH: Weinheim, 2003; 524 pages.
Institut Charles Sadron 9 An Unprecedented Number of “Reagents“ for LbL-Deposition
linear tacticity branched degree of polymerization Reagents: polymers (starshaped) composition copolymers monomer sequence
polymeric size polydispersity colloids metallic oxidic composition surface functionality
proteins biomacromolecules polynucleotides bioaggregates
small molecules ...... small & complex ions . . .
Multilayer Thin Films: Sequential Assembly of Nanocomposite Materials; Decher, G. and Schlenoff, J. B., eds., Wiley-VCH: Weinheim, 2003; 524 pages.
Institut Charles Sadron 10 An Example of the integration of nanoparticles into the films
Schmitt, J.; Decher, G.; Dressik, W. J.; Brandow, S. L.; Geer, R. E.; Shashidhar, R.; Calvert, J. M. Metal Nanoparticle/Polymer Superlattice Films: Fabrication and Control of Layer Structure. Adv. Mater. 1997, 9, 61-65.
Institut Charles Sadron 11 LbL Deposition (Programmed Assembly)
Advantages: deposition on surfaces of almost any kind and any shape broad processing window many control parameters: concentration adsorption time ionic strength solvent composition temperature . . .
Multilayer Thin Films: Sequential Assembly of Nanocomposite Materials; Decher, G. and Schlenoff, J. B., eds., Wiley-VCH: Weinheim, 2003; 524 pages.
Institut Charles Sadron 12 A bit of History (1):
It all started with “Bola”-Amphiphiles
0.60
0.50 Substrate Adsorption Adsorption 0.40
Bola-dianion Bola-dication 0.30
0.20
Absorbance @ 262 nm 0.10 Abs. biphenyl @ 262 nm 0.00 0 5 10 15 20 25 30 35 40 Number of Layers
G. Decher, J.-D. Hong, Makromol. Chem., Macromol. Symp. 46, 321-327 (1991) 420 ISI-Citations (as of January 2006)
Institut Charles Sadron 13 A bit of History (2): the next step were mixed bola/polyelectrolyte films
0.10
0.08 Adsorption Adsorption 0.06 Polyanion Bola-dication Absorbance
0.04
0.02 Abs. phenyl @ 225 nm Abs. biphenyl @ 262 nm 0.00 0 1 2 3 4 5 6 7 8 Number of Layers
G. Decher, J.-D. Hong, Ber. Bunsenges. Phys. Chem. 95, 1430-1434 (1991) 409 ISI-Citations (as of January 2006)
Institut Charles Sadron 14 A bit of History (3): and finally polyanion/polycation multilayers
0.15 225 nm Adsorption Adsorption 0.10 Polyanion Polycation
0.05 Absorbance @
Abs. phenyl @ 225 nm 0.00 0 5 10 15 20 25 30 35 40 Number of Layers
G. Decher, J.-D. Hong, J. Schmitt, Thin Solid Films 210/211, 831-835 (1992) 729 ISI-Citations (as of January 2006)
Institut Charles Sadron 15 A Small List of Polyions Already Used for Multilayer Fabrication
SO - 3 O- Na+ - + N OSO3 Na NH NH+ • SO2 O O NH S SO - Na+ 3 HO3S HO3S HN N N
- CO2 OH Na+
NaPSS PVS PAZO PAPSASPAN PTAA PAMPSA
H + + NH2 S N Cl - N NH + Cl- + 3 N N H N + 2 Cl - R HN N + N I - N S+ Cl - HN
NH2
PSMDEMA PAH Pre-PPV PDDA PMPyA R-PHPyV PEI
Institut Charles Sadron 16 Fine-tuning the film thickness by ionic strength (X-ray reflectometry) (Addition of salt yields thicker layers; polyanion from600 salt, polycation from pure water)
1011
109 50 alt. layers 500
107 42 alt. layers 400 105 30 alt. layers
103 300 20 alt. layers 1 10 Film Thickness [Å]
16 alt. layers 1.0 m NaCl 10-1 200 (17.7 Å / layer pair) Reflected X-ray Intensity [a.u.] X-ray Intensity Reflected 1.5 m NaCl 12 alt. layers (19.4 Å / layer pair) -3 2.0 m NaCl 10 (22.6 Å / layer pair) 100 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5 1015202530 Scattering Angle 2 [deg.] Number of PSS-Layers
G. Decher and J. Schmitt, Progr. Colloid Polym. Sci. 89, 160-164 (1992) 193 ISI-Citations (as of January 2006)
Institut Charles Sadron 17 Inversion of surface charge with deposition of each layer
Adsorption of polycations 40 PEI poly(ethylene imine) (PEI) and PAH poly(allyl amine) (PAH) renders the PAH PAH PAH PAH poly(allyl amine) (PAH) renders the surface positively charged. The 20 deposition of poly(styrene sulfonate) (PSS) yields a negative surface charge. Similar measurements were also 0 obtained from other groups.
For a theory of surface charge -20 inversion see M. Castelnovo and J. F.
Zeta Potential [mV] Zeta Joanny, Langmuir 16(19), 7524-7532 PSS PSS PSS PSS PSS (2000) and for a mechanism of -40 multilayer formation see J. B. bare SiO surface 2 Schlenoff and S. T. Dubas, Macromolecules 34(3), 592-598 0 5 10 15 20 25 30 35 40 (2001). Number of Measurement
G. Ladam, P. Schaad, J. C. Voegel, P. Schaaf, G. Decher, and F. Cuisinier, Langmuir 16(3), 1249-1255 (2000).
Institut Charles Sadron 18 QCM-D (Q-Sense D300), Q-Sense AB, Gothenburg, Sweden, unpublished data
Institut Charles Sadron 19 Automatic Layer Deposition Using a “Dipping” Robot
Automated deposition device, R&K Ultrathin Organic Film Technology, Berlin, Germany
Institut Charles Sadron 20 Deposition conditions are (in general) not really crucial
PEI/(PSS/PAH) on quartz from x M NaCl PEI/(PSS/PAH) on quartz from x M NaCl 5 5 manual dipping; dried after every layer automated device; no intermediate drying
0.15 300 0.15 300
0.14 280 0.14 280 260 260 0.13 0.13 D [Å] 240 D [Å] 240 0.12 0.12 220 220 0.11 200 0.11 200 A @ 226 nm A @ 226 nm A @ 226 0.10 180 0.10 180 160 160 0.09 0.09 140 140 0.08 0.08 0.4 0.6 0.8 1.0 1.2 1.4 1.6 0.4 0.6 0.8 1.0 1.2 1.4 1.6 c c NaCl NaCl A @ 226 nm D [Å] A @ 226 nm D [Å]
y = m1 + m2*m0 y = m1 + m2*m0 y = m1+m2*m0 y = m1+m2*m0 Value Error Value Error Value Error Value Error m1 0.054 0.002 m1 67 15 m1 0.059 0.006 m1 74 1 m2 0.061 0.003 m2 146 15 m2 0.063 0.006 m2 150 1 Chisq 6.8405e-06 NA Chisq 243.12 NA Chisq 4.3167e-05 NA Chisq 1.151 NA R 0.99822 NA R 0.98912 NA R 0.98951 NA R 0.99995 NA
However, dependence on ionic strength is stronger than in one of the previous cases since both polyions are deposited from saline solutions
Institut Charles Sadron 21 From Neutron Reflectivity Curves: Number of Deuterated Layers, Layer Positions and Layer Profiles
107 8.0 10-6
-6 105 7.0 10 ] -2 6.0 10-6 [Å 3 n 10
5.0 10-6
101 4.0 10-6
3.0 10-6 10-1
2.0 10-6 Reflected Intensity (Neutron) Intensity Reflected -3
10 Scattering Length Density 1.0 10-6
10-5 0.0 100 0 0.02 0.04 0.06 0.08 0.1 0 500 1000 1500 2000 2500 Q [Å-1 ] z Z [Å] M. Lösche, J. Schmitt, G. Decher, W. G. Bouwman, and K. Kjær, Macromolecules 31, 8893-8906 (1998) 190 ISI-Citations (as of January 2006) Institut Charles Sadron 22 Large surfaces are coated by spraying
Albert Izquierdo and Claudine Porcell Institut Charles Sadron 23 High-Speed Layer-by-Layer Deposition
15 min. / layer 6 sec. / layer
50 -150 times faster
A. Izquierdo, S. S. Ono, J.-C. Voegel, P. Schaaf, and G. Decher, Langmuir 2005, 21, 7558-7567
Institut Charles Sadron 24 A “real world” Biomedical Application: Contact Lenses Equipped with a Multilayer Coating
Photo courtesy of L. Winterton (CIBA-Vision), presented on occasion of the 223rd ACS National meeting April 7-11, 2002.
Partially based on US Patent US 520 8111, G. Decher & J.-D. Hong
Institut Charles Sadron 25 Surface Wettability
• Silicones are hydrophobic • Notoriously non-wetting • Require Surface modification
– Retain the key physical properties of the bulk while modifying only the outermost surface to achieve wettability
Photo courtesy of L. Winterton (CIBA-Vision), presented on occasion of the 223rd ACS National meeting April 7-11, 2002.
Institut Charles Sadron 26 Contact angle measurements on an uncoated (left) and LbL coated contact lens (right)
Photos courtesy of L. Winterton (CIBA-Vision), presented on occasion of the 223rd ACS National meeting April 7-11, 2002.
Institut Charles Sadron 27 Focus® Excelens™, a contact lens by CIBA-Vison.
After 12 years of steadily growing research in academia, CIBA-Vision announced the first commercially available product equipped with a multilayer coating.
Photo courtesy of L. Winterton (CIBA-Vision), presented on occasion of the 223rd ACS National meeting April 7-11, 2002.
Partially based on US Patent US 520 8111, G. Decher & J.-D. Hong
Institut Charles Sadron 28 Film Architectures Allowing to Control the Access of Cells to Neighboring Functional Layers: Tailored Bio-Interfaces
Monocytes accessing an embedded layer of Protein A, by developing extensions called pseudopods. This behavior is controlled/suppressed by choosing the chemical composition of the individual layers within the film architecture. N. Jessel, F. Atalar, Ph. Lavalle, J. Mutterer, G. Decher, P. Schaaf, J.-C. Voegel and J. Ogier Adv. Mater. 15(9) (2003), 692-695 Institut Charles Sadron 29 TNF- secretion as a function of layer composition
Poly-L-Lysine A
Poly-D-Lysine B
N. Jessel, F. Atalar, Ph. Lavalle, J. Mutterer, G. Decher, P. Schaaf, J.-C. Voegel and J. Ogier Adv. Mater. 15(9) (2003), 692-695 Institut Charles Sadron 30 A “real world” Application : “Yasa-Sheets” Equipped with a Multilayer Coating
The Yasa-sheet, invented by S. Shiratori of Keio University, is equipped with a multilayer film and contains an enzyme (extracted from bamboo) that controls the ethylene concentration and such extends the shelf-life of fruits and vegetables.
The product, sold by PLUSTO (Japan), received the „Excellent Product Award“ of Nikkei in 2001.
Image and movie are taken from the PLUSTO website. Institut Charles Sadron 31 Institut Charles Sadron 32 Metal Rubber™ (NanoSonic Inc.)
Metal Rubber, fabricated by layer-by-layer assembly by the company NanoSonic in Blacksburg, Virginia, is claimed to combine low modulus (about 10 MPa) with almost metal-like electrical conductivity (sheet resistance as low as 0.1 / . Temperature resistance up to 160 °C, highly resistant against aggressive solvents. The properties are maintained over millions of cycles. Product information from NanoSonic. Photo from: Popular Science, August 2004, page 36
Partially based on US Patent US 520 8111, G. Decher & J.-D. Hong
Institut Charles Sadron 33 Surfaces of Any Kind and Any Shape ? Here is an example of hollow multilayer capsules made by templating on colloidal particles
First, deposit polyelectrolytes on a micron-sized colloid
Then dissolve the colloid core
E. Donath, G. B. Sukhorukov, F. Caruso, S. A. Davis, and H. Möhwald, Angew Chem Int Ed 37, 2202-2205 (1998).
Institut Charles Sadron 34 Multilayers of PAH and PSS on 13nm Colloids Easy Access to Stable (Bio)functional Nanoparticles
Grégory Schneider and Gero Decher, Nano Lett., Vol. 4, No. 10, 2004, 1832-1839
Institut Charles Sadron 35 Can be made on ANY surface Control of composition Dierent colors represent dierent functionalities Examples: polymers, proteins, nanoparticles, … nanoscale Components can be fixed or 50 nm mobile Porosity control, … to macroscale 5 mm Molecular scale (0.5 to 10 nm)
Institut Charles Sadron 36 LbL - the ONE does it ALL nano-coating solution
Technological advantages over competitive techniques: (Langmuir-Blodgett, self-assembled monolayers, covalent coupling, grafting from, grafting to, spin coating, ...)
• Broadness, Integrateability, Adaptability, ... • Choice of components (bio/macro)molecules, colloids, ... • Choice of surfaces (any size, any shape) • Choice of solvent (water, others are possible) • Patternability • Quality control (chemical purity, homogeneity, reproducibility) • Overall device yield
All competitive techniques are limited (if not fail) with respect to several items of this list (in comparison with LbL) However, LbL can easily be integrated with most competitive techniques !
pseudo - inconvenience of LbL: • Number of proccessing steps - increases with number of components - increases with numbers of layers - BUT it just means adding a beaker (baths) to the deposition chain
Institut Charles Sadron 37 The Field is Rapidly Expanding
120 number of publications / year The first symposium on 500 total number of publications Polyelectrolyte Multilayers 100 Was held on occasion of the 400 American Chemical Society National Meeting - Colloid Division 80 San Francisco, Ca., March 26-31, 2000 Joseph B. Schlenoff, Gero Decher, organizers 300
60 More Symposia: 223rd ACS National Meeting Orlando, Florida, April 7-11, 2002 200 226th ACS National Meeting 40 New York, Sept. 7-11, 2003 227th ACS National Meeting Anaheim, Ca. March 28-April 1, 2004 100 20
Source: P. Bertrand, A. Jonas, A. Laschewsky and R. Legras 0 0 1990 1992 1994 1996 1998 2000 Macromol. Rapid. Commun. 21 (2000), 319-348
publication year
Institut Charles Sadron 38 A list of recent reviews, newsletters and books:
(1) Decher, G., Layered Nanoarchitectures via Directed Assembly of Anionic and Cationic Molecules; in: Comprehensive Supramolecular Chemistry, Vol. 9, "Templating, Self-Assembly and Self-Organization" (Sauvage, J.-P. and Hosseini, M. W., Eds.), Pergamon Press: Oxford, 1996; 507-528.
(2) Decher, G., Fuzzy Nanoassemblies: Toward Layered Polymeric Multicomposites, SCIENCE 1997, 277, 1232-1237.
(3) Decher, G.; Eckle, M.; Schmitt, J.; Struth, B., Layer-by-Layer assembled multicomposite films. Curr. Opinion Coll. & Interf. Sci. 1998, 3, 32-39.
(4) Bertrand, P.; Jonas, A.; Laschewsky, A. and Legras, R., Ultrathin polymer coatings by complexation of polyelectrolytes at interfaces: suitable materials, structure and properties. Macromol. Rapid. Commun. 2000, 21, 319- 348.
(5) Paula T. Hammond, Recent explorations in electrostatic multilayer thin film assembly. Curr. Opinion Coll. & Interf. Sci. 2000, 4, 430-442.
(6) Michael Freemantle, C&EN: Science & Technology - Polyelectrolyte Multilayers, Chemical & Engineering News, May 6 (2002), Vol. 80 (18), pp. 44-48
(7) Jessica Gorman, Layered Approach: A simple technique for making thin coatings is poised to shift from curiosity to commodity, Science News, Week of Aug. 9, 2003; Vol. 164, No. 6
(8) Multilayer Thin Films: Sequential Assembly of Nanocomposite Materials; Decher, G. and Schlenoff, J. B., eds., Wiley- VCH: Weinheim, 2003; 524 pages.
Institut Charles Sadron 39 Multilayer Thin Films - For more information: Sequential Assembly of Nanocomposite Materials
Decher, G. / Schleno, J. B. (eds.) With a Foreword by Jean-Marie Lehn
Wiley-VCH, Weinheim, Germany, 2003, 524 pages ISBN 3-527-30440-1
Chapters from: G. Decher (Inst. Charles Sadron), V. Kabanov (Moscow State University), J. F. Joanny (Institut Curie), J. Schleno (Florida State University), M. Rubner (MIT), T. Kunitake and Y. Lvov (RIKEN and Louisiana State University), A. Jonas (University of Louvain-la-Neuve), N. Kotov (Oklahoma State University), J. Fendler (Potsdam, USA), P. Hammond (MIT), J. Shen and X. Zhang (Jilin University), F. Caruso and G. Sukhorukov (MPI-KG), H. Möhwald (MPI-KG), D. Kurth and R. v. Klitzing (MPI-KG and TU Berlin), B. Tieke (University of Cologne), R. Claus (Viginia State University), and M. Brüning (Michigan State University)
Institut Charles Sadron 40