Nitroxide-Mediated Polymerization-Induced Self-Assembly of Block Copolymers at the Surface of Silica Particles: Toward New Hybrid Morphologies

Abstract

Silica/polymer latexes with concentric core–shell–corona, half-capped, snowman-like vesicular, tadpole- and centipede-like morphologies have been produced by nitroxide-mediated polymerization-induced self-assembly (PISA) performed in the presence of aqueous suspensions of colloidal silica. A hydrosoluble brush-like PEO-based macroalkoxyamine (P[(poly(ethylene oxide) methyl ether methacrylate)12-co-styrene]-SG1, Mn = 11 700 g mol–1 and Mw/Mn = 1.11) was first adsorbed onto the surface of submicronic silica particles. The obtained suspension was then used in the emulsion polymerization of n-butyl methacrylate with 8 mol % of styrene. This led to the formation of amphiphilic block copolymers (BCPs) that self-assembled in situ at the silica surface into well-defined hybrid nano-objects of various morphologies, in agreement with the principles of polymerization-induced micellization. The influence of the pH was more specifically investigated, using silica particles of different size ranging from 30 to 230 nm. ...