Synthesis of poly(sodium styrene sulfonate)-b-poly(butyl acrylate) block copolymers via RAFT emulsifier-free emulsion polymerization and their application in PEDOT aqueous dispersions

The amphiphilic block copolymers of poly(sodium styrene sulfonate)-b-poly(butyl acrylate) (PSS-b-PBA) with different block molar ratios were synthesized via RAFT surfactant-free emulsion polymerization. Poly(3,4-ethylenedioxythiophene) aqueous dispersions (PEDOT:PSS-b-PBA) were prepared with PSS-b-PBA block copolymers as the templates. The composition and performance of PSS-b-PBA and PEDOT:PSS-b-PBA were investigated. Results showed that the amphiphilic PSS-b-PBA block copolymers were successfully synthesized via RAFT surfactant-free emulsion polymerization in a controlled way and the composition of the block copolymers were confirmed by Nuclear Magnetic Resonance (NMR) spectrum and Thermogravimetric Analysis (TGA). PSS-b-PBA block copolymers formed micelles in aqueous matrix and the critical micelle concentrations (cmc) were found to be around 10−6 g mL−1, which were determined by fluorescence spectrometry method. The stable PEDOT aqueous dispersions were fabricated using the amphiphilic PSS-b-PBA block copolymers as the templates. The block molar ratio of the block copolymers had little effects on the polymerization kinetics of EDOT. But the conductivity of the PEDOT film was greatly enhanced when the block copolymers were used as the templates, which was supposed to be caused by the core-shell structure of the block copolymers.