Stimuli-responsive nanoparticles from RAFT dispersion polymerization-induced self-assembly (PISA) of N-phenylacrylamide copolymerized with a boronic acid-substituted derivative

Abstract

Boronic acid (BA) moieties confer a variety of stimuli-response properties upon polymers. PISA is the most efficient technique for the preparation of core–shell nanoparticles (NPs), however aqueous dispersion PISA of free BA-containing monomers is complicated by the formation of the boroxine anhydride at the hydrophobic core. In the present work, dispersion reversible addition-fragmentation chain transfer (RAFT) copolymerization of a free BA-containing derivative of N-phenylacrylamide yields NP morphologies which are different to those formed from the equivalent PISA homopolymerization without BA. Depending on conditions, PISA results in spheres, rods, and worms with colloidal stability improved by using a higher fraction of the non-stimuli responsive monomer to give large compound micelles. Post-polymerization stimuli-response from the resultant PISA dispersion through hydrolysis of boroxine-rich copolymer NPs by dilution with the aqueous dispersion solvent or with water yields micron-sized worms, lamellae, and vesicles. Self-assembly to higher order morphologies is driven by the extent of hydrolysis. The resultant free BA-containing NPs becoming smaller and spherical upon basification and glucose addition.