Responsive Nanoassemblies via Interpolyelectrolyte Complexation of Amphiphilic Block Copolymer Micelles

Shell “locked” nanoassemblies ranging in size from 34 to 78 nm have been prepared from interpolyelectrolyte complexation of block copolymer micelles of poly[(N,N-dimethylacrylamide)-b-(N-acryloylalanine)-b-(N-isopropylacrylamide)] with the homopolymer poly(ar-vinylbenzyl)trimethylammonium chloride above the unimer to micelle phase transition temperature of the block copolymer in water. Of technological significance is the reversibility of the shell cross-linking by addition of 0.4 M NaCl, allowing micelle dissociation below the lower critical solution temperature of the copolymer micelles. Poly(N-acryloylalanine) (AAL) and block copolymers were prepared directly in water via controlled reversible addition fragmentation chain transfer (RAFT) polymerization utilizing mono- and difunctional poly(N,N-dimethylacrylamide) macroCTAs.