Surface Grafting of Polymers Via Living Radical Polymerization Techniques; Polymeric Supports for Combinatorial Chemistry
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Surface grafting of polymers via living radical polymerization techniques; polymeric supports for combinatorial chemistry By Nikolas Anton Amadeus Zwaneveld A thesis submitted in fulfillment of the requirements for the degree of Doctor of Philosophy School of Chemical Engineering and Industrial Chemistry University of New South Wales Sydney, Australia March, 2006 ii iii Abstract The use of living radical polymerization methods has shown significant potential to control grafting of polymers from inert polymeric substrates. The objective of this thesis is to create advanced substrates for use in combinatorial chemistry applications through the use of γ-radiation as a radical source, and the use of RAFT, ATRP and RATRP living radical techniques to control grafting polymerization. The substrates grafted were polypropylene SynPhase lanterns from Mimotopes and are intended to be used as supports for combinatorial chemistry. ATRP was used to graft polymers to SynPhase lanterns using a technique where the lantern was functionalized by exposing the lanterns to gamma-radiation from a 60Co radiation source in the presence of carbon tetra-bromide, producing short chain polystyrene tethered bromine atoms, and also with CBr4 directly functionalizing the surface. Styrene was then grafted off these lanterns using ATRP. MMA was graft to the surface of SynPhase lanterns, using γ-radiation initiated RATRP at room temperature. It was found that the addition of the thermal initiator, AIBN, successfully increased the concentration of radicals to a level where we could achieve proper control of the polymerization. RAFT was used to successfully control the grafting of styrene, acrylic acid and N,N’- dimethylacrylamide to polypropylene SynPhase Lanterns via a γ-initiated RAFT agent mediated free radical polymerization process using cumyl phenyldithioacetate and cumyl dithiobenzoate RAFT agents. Amphiphilic brush copolymers were produced with a novel combined RAFT and ATRP system. Polystyrene-co-poly(vinylbenzyl chloride) created using gamma-radiation and controlled with the RAFT agent PEPDA was used as a backbone. The VBC moieties were then used as initiator sites for the ATRP grafting of t-BA to give a P(t-BA) brush that was then hydrolyzed to produce a PAA brush polymer. iv FMOC loading tests were conducted on all these lanterns to assess their effectiveness as combinatorial chemistry supports. It was found that the loading could be controlled by adjusting the graft ratio of the lanterns and had a comparable loading to those commercially produced by Mimotopes. v Declaration I hereby declare that this submission is my own work and to the best of my knowledge it contains no material previously published or written by another person, nor material which to a substantial extent has been accepted for the award of any other degree or diploma at UNSW or any other educational institution, except where due acknowledgement is made in the thesis. Any contribution made to the research by others, with whom I have worked at UNSW or elsewhere, is explicitly acknowledged in the thesis. I also declare that the intellectual content of this thesis is the product of my own work, except to the extent that assistance from others in the project’s design and conception or in style, presentation and linguistic expression is acknowledged. __________________________ Nikolas Zwaneveld vi Acknowledgements It has been an epic, oh such an epic… and there are many people who I owe so much to. Firstly I must thank Julia and my family; Solara, Ansel, Lisa and Andrew, because without their love and support I would never have made it this far. Next I must thank all those who have helped me academically to do this thesis; I need to thank Prof. Tom Davis, Christopher Barner-Kowollik and Hans Heuts who have been my supervisors throughout this thesis. Beyond my supervisors I have had the help of three great people who have poured hours if not weeks or months of their lives into helping me with my work; Tony Granville, Leonie Barner, Francoise Isaure. Without your help there is absolutely no way I would ever have finished this. I owe you all an infinite debt. My thanks goes especially out to Tony who not only edited the entirety of my thesis but also solved so many theoretical problems, helped with so much of my experiments and showed me the way into the light at the end of the tunnel. I would also like to thank Martina Stenzel, who always showed an amazing amount of interest in my work and kept me inspired. I truly need to thank Mimotopes for their sponsorship of this project and the people there who have helped me out so much, Senake Perera, Francesca Ercole, Nick Ede. I need to also thank all those people from the School of Chemical Engineering and Industrial Chemistry who not only would seem to make the impossible happen for me on short notice but also have become fantastic friends of mine; A/Prof. Mike Brungs, Prof. Rob Burford, Phil McAuley, John Starling, Phil and Paul from the workshop and many others. Especially I’d like to thank Istvan (Steve) who has become a great friend of mine and has helped me so many times throughout my thesis that I can’t even begin to count. Not only can he cook and brew, but the raw meat that he serves up is second to none. vii In my many years at CAMD I need to thank all my friends who have come and gone. Especially I’d like to thank the Frenchies; Seb, Julien, Arnaud “bonjour salaud” Favier, Francoise who have always been an unending source of good humor. You have shown me that life should be a proper mix of work, soccer, beer and late nights. The Swedish; Niklas, Ingmar, Camila and Daniel thanks for teaching me about licorice with ammonia, Christmas crayfish, schnapps, and snus. The absent Dutchmen, Hans Heuts and Almar Postma who have been a great help and better friends despite being 1000s of kilometers away for most of my thesis. Mikey Whittaker who not only helped me with my work but who extended a hand in friendship that was always available. Thanks to Antonio and Nathan all those who would help me analyze HLUG’s over a cup of coffee. Thanks to the old-school boys Lachlan Yee, Dr Dave, Mr Dave, Evan, Henry, Joan and Simon who were around when it all began. Maribel our little Mexican girl, who I don’t think has ever not had a smile on her face the whole of her life. Nicole and Philipp Vana with whom I have developed a friendship that will last forever. Luca who showed me that Italian largely consists of random swear words strung together into a sentence. To all my friends who concertedly tried to distract me from ever finishing, specifically; Gareth ‘just one more…’ Milton, Romily Webster, Daniel ‘in a cave’ Luong Van, Nathan Allan, Shawn ‘the wookie’ Sijnstra, Clare Hayward, Iain Findlay, Mike ‘I’ve got the full set’ Wheatley, Helen Vafiads, Angella Barrett, Shane Cox, Stefan Kaufman, all the doomies, Domus Luni, Lyon La Foret, the cricket boys and all those I’ve forgotten to mention. A large thank you goes to those who corrected my engrish in my thesis, it wood be much worze if you not me correct. Thanks to Tom Murtagh, Rom, Dan, Shawn, Solara and of coarse Tony for fixing it all up goodly like and removing those words I just made up. Everyone else who has helped me out during my time, I thank you all. It’s finished, it’s done…and now I can’t brain anymore. viii Table of Contents Abstract...........................................................................................................................iii Declaration.......................................................................................................................v Acknowledgements.........................................................................................................vi Table of Contents .........................................................................................................viii Abbreviations ...............................................................................................................xiv 1. Introduction.............................................................................................................1 1.1. Aims of the investigations.................................................................................1 1.2. Outline of the thesis ..........................................................................................1 1. Introduction................................................................................................................................ 1 2. Theoretical background ............................................................................................................. 1 3. Analysis techniques and synthesis of reagents........................................................................... 1 4. Graft polymerization from SynPhase lanterns using ATRP ...................................................... 2 5. Gamma-radiation initiated reverse ATRP grafting polymerization ........................................... 2 6. Reversible Addition-Fragmentation Chain Transfer Polymerization of styrene........................ 3 7. RAFT mediated grafting of fast polymerizing-hydrophilic monomers...................................... 3 8. Conclusions................................................................................................................................ 4 9. Appendix 1................................................................................................................................. 4 10. Appendix 2..............................................................................................................................