Fluorinated amphiphilic block copolymers via RAFT polymerization and their application as surf-RAFT agent in miniemulsion polymerization

This investigation reports the preparation of amphiphilic block copolymer (Am-BCP) based on poly(ethylene glycol) methyl ether methacrylate (PEGMA) and 2,2,3,3,4,4,4-heptafluorobutyl acrylate (HFBA) via RAFT polymerization. In this case poly(PEGMA) (PPEGMA) was prepared using 2-cyano-2-propyl dithiobenzoate (CPBT) as a RAFT agent. This PPEGMA was later used as a macro-RAFT agent for the polymerization of HFBA to prepare well-defined block copolymers (BCPs), (PPEGMA-b-PHFBA) of varied lengths and compositions. The BCPs self-assembled in aqueous solution to produce spherical micelles consisting of hydrophobic block PHFBA as a core and a hydrophilic block of PPEGMA as a flexible corona. This Am-BCP formed micelles of different sizes, as characterized by dynamic light scattering (DLS) and TEM analyses. The Am-BCP was later used as a surf-RAFT agent i.e. as a surfactant as well as a macro-RAFT agent for the miniemulsion polymerization of styrene. TEM analysis showed that the synthesized polystyrene emulsion had a core-shell morphology. The particle size and particle size distributions of the polystyrene latex were determined by DLS analysis.