PH-responsive "Smart surface coatings"

Abstract

A diblock copolymer poly(2-(dimethylamino)ethyl methacrylate)-block-poly(2- (diethylamino)ethyl methacrylate) (PDEAEMA-b-PDMAEMA) was prepared via reversible addition fragmentation chain transfer (RAFT) polymerization, using 2-cyanoisopropyl dithiobenzoate (CPDB) as the RAFT agent. Characterization of these polymers by 1H NMR and size exclusion chromatography (SEC) indicated that the copolymers had a well controlled microstructure. The micellization behavior of this copolymer sample, in aqueous solution, was investigated by dynamic light scattering and AFM; a reversible unimer to micelle transition at pH∼7.5 was seen with the micelles formed at higher pHs. After deposition of a monolayer of micelles at the solid-liquid interface, contact angle measurements as a function of pH showed that a pH-responsive surface-coating had been obtained.