A cationic fluorosurfactant for fabrication of high-performance fluoropolymer foams with controllable morphology

Abstract

High internal phase emulsion (HIPE) technique has been of great interest for fabrication of polymer foams with controlled porous structures. However, for fluoropolymers, it has been a challenge to fabricate high-performance foams with controllable porous structures by HIPE due to the lack of suitable surfactant. Here, for the first time, a new type of cationic fluorosurfactant (CFS) is proposed to address this issue. The cationic fluorosurfactant is a diblock copolymer, Poly(2-dimethylamino)ethyl methacrylate-b-Poly(hexafluorobutyl acrylate) (PDMAEMA-b-PHFBA) synthesized by reversible addition−fragmentation chain transfer (RAFT) polymerization. For the prepared fluoro-diblock copolymer having similar fluorosegments to fluoro-monomer, this cationic fluorosurfactant can effectively stabilize high internal phase emulsion (HIPE) system involving hexafluorobutyl acrylate monomer as oil phase, water as internal phase, DVB as cross linker and AIBN as an initiator. Polymerization of the HIPE system finally gave rise to novel flexible fluoropolymer foam, Poly(HFBA-DVB) with a porous morphology which can be tuned simply by the amount of the fluorosurfactant. As a high-performance porous material, the fluoropolymer foam demonstrated not only significant capacities and fast adsorption kinetic for separating various organic oils from water, but also has an excellent thermal stability up to 340°C, indicating significant applications at extreme conditions.