Formation and Properties of Vesicles from Cyclic Amphiphilic PS-PEO Block Copolymers.

Linear polystyrene-poly(ethylene oxide)-polystyrene (PS-PEO-PS) block copolymers and corresponding cyclized PS-PEO counterparts with three different PS molecular weights were synthesized and self-assembled to investigate the effects arising from the topology. Linear PS-PEO-PS (L1) and cyclic PS-PEO (C1) formed micelles. As previously reported for poly(n-butyl acrylate) and PEO block copolymers, the micelles from C1 showed more than 30 °C higher phase transition temperature (cloud point, T) than those from L1.