Complexes Covered with Phosphorylcholine Groups Prepared by Mixing Anionic Diblock Copolymers and Cationic Surfactants.

Anionic diblock copolymers (PA) composed of biocompatible polybetaine, poly(2-(methacryloyloxy)ethyl phosphorylcholine) (PMPC), and anionic poly(sodium 2-(acrylamido)-2-methylpropanesulfonate) (PAMPS) were synthesized via reversible addition-fragmentation chain transfer (RAFT) radical polymerization. Two types of diblock copolymers (PA and PA) were prepared with different compositions. The PA/CTAB complexes were formed by a stoichiometrically charge-neutralized mixture of anionic PA and cationic cetyltrimethylammonium bromide (CTAB) micelles in water. The complexes prepared using PA and PA were vesicles and micelles, respectively, and were covered with hydrophilic PMPC shells. The complexes dissociated upon addition of NaCl because the complex was maintained through electrostatic interactions. The PA/CTAB vesicles could encapsulate uncharged hydrophilic guest molecules into the interior of the aqueous phase.