Synthese van geconjugeerde blok-copolymeren: Geadvanceerde structuren en polymerisatiemethoden

pi-Conjugated polymers are a promising class of materials because of the ir exceptional optic and electronic properties. They are used in high te ch applications, e.g. organic solar cells, organic LEDs, supercapa citors, biosensors. Their molecular architecture and structure play a do minant role in their performance and therefore obtaining control over th eir synthesis is one of the main goals polymer chemists pursue nowadays. Building predetermined molecular structures with low molar mass distrib utions was the challenge in the past and will continue to be so in the f uture. The major breakthrough was the discovery of the Kumada catalyst-t ransfer polymerization of P3AT with Ni(dppp)Cl2 as a catalyst by the res earch groups of Yokozawa and McCullough in 2004. A controlled chain-grow th polymerization mechanism was demonstrated for this class of materials nd enabled the possibility to develop block-copolymers and other topologies in a one-pot synthesis. In a first part, this manuscript desc ribes the research performed to quantify the emarkable behavior of the catalyst leading to the chaingrowth character. An in-depth 1H NMR study was used to assign the different end-groups of the polymer ch ains. Next, this polymerization technique is exploited to develop block- copoly(3-alkylthiophene)s in which both blocks exhibit a different solub ility in the solvents used. While the solubility difference in the first set of synthesized block-copoly(3-alkylthiophene)s originates from a di fferent length of the alkyl side chains, a more pronounced and tunable d ifference, based on the presence of amine-functions in one of both block s, is obtained in the next group. The introduction of chiral centers in one of both blocks makes a chiroptical investigation possible. In a next part, the possibility to transform the polymerization of the h elically poly(3,6-[9,10-di(octyloxy)]phenantrene), traditionally synthes ized via a step-growth process, into a controlled polymerization is inve stigated. Therefore, the current chain-growth polymerization techniques presented in literature are applied and investigated using MALDI-ToF spe ctrometry and GPC. Although the current chain-growth mechanisms are well-established for pa rticular classes of conjugated polymers, they are far from universal whi ch hinders the unlimited formation of block-copolymers in a simple one-p ot synthesis. To overcome this issue, a new chain-growth polymerization protocol for the synthesis of conjugated polymers is introduced in the l ast part of this thesis. This protocol, based on a Negishi coupling with a Pd(Ruphos) catalyst, does not rely on any systemdependent interaction s, as was the case for the current mechanisms. After the study on the ch ain-growth behavior of P3AT, poly(3-alkylselenophene) and poly(9,9-dialk ylfluorene), ABC tri-blockcopolymers are synthesized with the new Pd(Rup hos) protocol and assessed with spectroscopic techniques and GPC.1. Introduction 1 2. An introductory tale … 7 3. Conjugated Polymers 11 3.1. Introduction 11 3.2. Optical and electronic properties 12 3.3. Solubility 17 4. Polymerization mechanisms for conjugated polymers 19 4.1. Introduction 19 4.2. Step-growth polymerizations 20 4.3. Chain-growth polymerizations 23 4.4. Conjugated block-copolymers 45 5. Aggregation behavior of conjugated polymers 53 5.1. Macromolecular vs. supramolecular behavior 53 5.2. UV-vis absorption and emission spectroscopy 54 5.3. Chirality in conjugated polymers 55 5.4. Circular dichroism spectroscopy 57 5.5. Chiral random- and block-copolymers 61 6. Aim of the dissertation 69 7. Quantitative analysis of the catalyst ring-walking process. 75 7.1. Introduction 75 7.2. The Kiriy model 76 7.3. Approach 76 7.4. Synthesis of a terthiophene model compound. 80 7.5. Determination of the stickiness parameter 80 7.6. AB- vs. BAB block-copolymers 83 7.7. Conclusion 85 7.8. Experimental Part 86 8. Block-copoly(3-alkylthiophene)s with different side chain lengths 91 8.1. Introduction 91 8.2. Approach 92 8.3. Monomer and polymer synthesis 94 8.4. 1H NMR analysis 96 8.5. Chiroptical analysis 100 8.6. Conclusion 106 8.7. Experimental Part 106 9. Amphiphilic block copoly(thiophene)s 113 9.1. Introduction 113 9.2. Approach 114 9.3. Monomer and polymer synthesis 116 9.4. GPC and 1H NMR analysis 119 9.5. Chiroptical analysis in solution 121 9.6. Chiroptical analysis in film 132 9.7. DSC analysis 140 9.8. Conclusion 141 9.9. Experimental Part 142 9.10. Appendix 149 10. Chain-growth polymerization of poly(phenanthrene)s 157 10.1. Introduction 157 10.2. Approach 158 10.3. Kumada-based mechanisms 159 10.4. Suzuki-based mechanism 160 10.5. Conclusion 170 10.6. Experimental part 171 11. Development of the chain-growth mechanism 177 11.1. Introduction 177 11.2. Approach 179 11.3. Design 180 11.4. Reaction conditions 181 11.5. Monomer synthesis 182 11.6. Synthesis of the initiators 184 11.7. Evaluation of the chain-growth behavior 185 11.8. Decomplexation of the catalyst 192 11.9. Di-block-copolymers 195 11.10. General relevance 198 11.11. Conclusion 199 11.12. Experimental part 200 12. Synthesis of all-conjugated tri-block-copolymers 209 12.1. Introduction 209 12.2. Approach 210 12.3. Choice of the Grignard reagent 210 12.4. Chain-growth character of poly(3-octylselenophene) 219 12.5. Synthesis of tri-block-copolymers 220 12.6. GPC analysis 223 12.7. 1H NMR analysis 226 12.8. UV-vis absorption and fluorescence spectroscopy 228 12.9. Conclusion 231 12.10. Experimental part 232 13. General Conclusion and Perspectives 247 14. Experimental Techniques 255 15. Heath, Safety & Environment 259 16. List of Publications 263nrpages: 312status: publishe