Cylindrical micelles from the living crystallization-driven self-assembly of poly(lactide)-containing block copolymers

Abstract

The synthesis and self-assembly of poly(lactide)-b-poly(acrylic acid) and poly(lactide)-b-poly(dimethylaminoethylacrylate) block copolymers by a combination of ring-opening polymerization and reverse-addition fragmentation chain transfer (RAFT) polymerization is reported. Self-assembly of block copolymers containing enantiopure homochiral poly(lactide), PLA, by a simple direct dissolution methodology results in core-crystallization to afford micelles with a cylindrical morphology. Amorphous atactic PLA cores and conditions that did not promote crystallization resulted in spherical micelles. Cylindrical micelles were characterized by transmission electron microscopy (TEM) with cryo-TEM, small angle neutron scattering (SANS) and angular dependent dynamic light scattering (DLS) proving that the cylindrical morphology was persistent in solution. Manipulation of the assembly conditions enabled the length and dispersity of the resultant cylindrical micelles to be controlled.