Preparation of mechanoresponsive hairy particles using polymeric surfactants in emulsion polymerization

We demonstrate that diblock copolymers comprising hydrophobic polystyrene and hydrophilic poly(acrylic acid) blocks connected by an off-center anthracene-maleimide Diels-Alder adduct mechanophore are mechanochemically active when sonicated in the form of micelles. Non-crosslinked and crosslinked hairy poly(butyl acrylate) latex particles were synthesized using amphiphilic block copolymers as stabilizers in emulsion polymerization. Both non-crosslinked and crosslinked hairy particles can be mechanically activated by sonication, which means that the "hairs" on the surface of particles can be selectively cleaved. The sensitivity to mechanical force enhanced with increasing crosslinking of the PBA particles, but it may also lead to particle degradation. The mechanoresponsive hairy latex particles may facilitate the design of stress-sensing probes in aqueous systems.