Aqueous solution properties of pH‐responsive AB diblock acrylamido–styrenic copolymers synthesized via aqueous reversible addition–fragmentation chain transfer

Here we report the synthesis and solution characterization of a novel series of AB diblock copolymers with neutral, water‐soluble A blocks consisting of N,N‐dimethylacrylamide and pH‐responsive B blocks of N,N‐dimethylvinylbenzylamine. To our knowledge, this represents the first example of an acrylamido–styrenic block copolymer prepared directly in a homogeneous aqueous solution. The best blocking order [with poly(N,N‐dimethylacrylamide) as a macro‐chain‐transfer agent] yielded well‐defined block copolymers with minimal homopolymer impurities. The reversible aggregation of these block copolymers in aqueous media was studied with 1H NMR spectroscopy and dynamic light scattering. Finally, an example of core‐crosslinked micelles was demonstrated by the addition of a difunctional crosslinking agent to a micellar solution of the parent block copolymer.