| Amphiphilic block copolymers are composed of distinct segments exhibiting different chemical properties. In solution, block copolymers may self-assemble to form micelles when triggered by a change in the environment. The effect of chain rigidity can be investigated in better detail if the molecular weights are controlled, as the polymer's ability to aggregate is also influenced by polymer size. Acrylate and methacrylate monomers were chosen for their similar chemical properties but their difference in reported glass transition temperature (Tg). Amphiphilic block copolymers were synthesized by a controlled free radical (RAFT) polymerization. 1H-NMR methods were developed to measure molecular weight of poly(methyl methacrylate) and poly(t-butyl acrylate) homopolymers to corroborate size-exclusion chromatography measurements. Using qualitative measurements of peak broadening that occurs by the shortening of T2 relaxation when polymers phase-separate from solution, it was found that polymers with a more rigid hydrophobic region tend to form micelles the most readily. |
