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Externally initiated o-tolyl initiated poly(3-hexylthiophene) (P3HT) was synthesized according to Grignard metathesis polymerization at varying chain length to compare number average molecular weights (Mn) obtained by gel permeation chromatography (GPC) and 1H NMR end group analysis. The extent of overestimation by GPC (1.3) was determined to be lower than previously reported for low Mn polymers. However, an apparent GPC quantification limit was observed as NMR Mn correlated well to predicted results. Static light scattering studies on high Mn polymers provided evidence that the true molecular weight was more similar to GPC-derived Mn. Despite nearly 100% external initiation efficiency, at a certain Mn limit new uninitiated chains may be synthesized. It is suggested that the synthesis of externally initiated P3HT should be limited to Mn below 40 kDa to ensure fully externally initiated chains. A proposal for the synthesis of externally initiated macrocyclic P3HT will also be discussed.

Externally initiated o-tolyl initiated poly(3-hexylthiophene) (P3HT) was synthesized according to Grignard metathesis polymerization at varying chain length to compare number average molecular weights (Mn) obtained by gel permeation chromatography (GPC) and 1H NMR end group analysis. The extent of overestimation by GPC (1.3) was determined to be lower than previously reported for low Mn polymers. However, an apparent GPC quantification limit was observed as NMR Mn correlated well to predicted results. Static light scattering studies on high Mn polymers provided evidence that the true molecular weight was more similar to GPC-derived Mn. Despite nearly 100% external initiation efficiency, at a certain Mn limit new uninitiated chains may be synthesized. It is suggested that the synthesis of externally initiated P3HT should be limited to Mn below 40 kDa to ensure fully externally initiated chains. A proposal for the synthesis of externally initiated macrocyclic P3HT will also be discussed.

In this study, the zwitterionic monomer [2-(methacryloyloxy)ethyl] dimethyl-(3-sulfopropyl) ammonium hydroxide (SBMA) was polymerized in a controlled manner by reversible addition-fragmentation chain transfer (RAFT) polymerization. The SBMA was also polymerized by atom transfer radical polymerization (ATRP) but in a less controlled manner why ATRP was discarded for further use in the study. The RAFT polymerized p(SBMA) was end-group modified through aminolysis forming a thiol end-group. The zwitterionic polymers have considerable anti-fouling properties and could be of use in contact lenses to prolong the wear-time. Model contact lens hydrogel substrates were synthesized, through free radical polymerization, consisting of 1/3 of silicone monomer, 2/3 of dimethyl acrylamide (DMA) and small percentages of glycidyl methacrylate (GMA) and ethylene glycol dimethacrylate (EGDMA) cross-linker. These had poor mechanical strength and could only be used to explore the effect of surface chemical modification. The p(SBMA)-thiol was ‘graftedto’, by applying thiol-epoxide ring-opening, at a free radical polymerized co-polymer consisting of DMA and GMA indicating that this could work for the model hydrogel surfaces. / I denna studie polymeriserades den zwitterjoniska monomeren [2- (metakryloyloxi) etyl] dimetyl (3-sulfopropyl) ammoniumhydroxid (SBMA) på ett kontrollerat sätt genom ”reversible additionfragmentation chain transfer” (RAFT) polymerisation. SBMA polymeriserades också genom “atom transfer radical polymerization" (ATRP) men på ett mindre kontrollerat sätt varför ATRP då förkastades för vidare användning i arbetet. p(SBMA) blev ändgruppsmodifierad genom aminolys som då bildade en tiol ändgrupp. Zwitterjoniska polymerer kan vara bra för att förhindra tillväxt av biofilmer/beläggningar och kan därför bidra till att användningstiden för kontaktlinser kan förlängas. Modellytor baserade på hydrogel framställdes genom friradikalpolymerisation, med syfte att efterlikna en kontaktlins. Modellmaterialet består av 1/3 av silikoninnehållande monomer, 2/3 av dimetylakrylamid (DMA) och små mängder glycidylmetakrylat (GMA) samt etylenglykoldimetakrylat (EGDMA) som tvärbindare. Dessa modellytor hade dålig mekanisk hållfasthet och kunde endast användas för att utvärdera effekterna av ytmodifiering. Genom att använda tiol-epoxi ring-öppning utav p(SBMA)-tiol på en sam-polymer bestående av (DMA) och (GMA) indikerade detta att "ympning-till" skulle kunna fungera för hydrogels modellytorna.

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