Fluorinated Block Copolymer as Steric Stabilizer for the Formation of Ionic Liquid-in-Compressed Carbon Dioxide Emulsions

摘要

A block copolymer poly(ethylene oxide)-b-poly(1,1,2,2-tetrahydroperfluorodecyl acrylate) PEO-b-PFDA of M_n=22800 g.mol~(-1) has been synthesized by living free-radical polymerization from a PEO-based trithiocarbonate chain transfer agent of M_n=2300 g.mol~(-1). As this fluorinated block copolymer was shown to be soluble in mild conditions of pressure and temperature in both liquid and supercritical CO_2, it was investigated as surfactant in 1-butyl-3-methyl imidazolium hexafluorophoshate/CO_2 system (bmim-PF_6/CO_2). In contrast to macroscopic phase separation in the absence of surfactant, the copolymer acted as an efficient steric stabilizer and allowed the formation of ionic liquid-in-CO_2 emulsions, which are of considerable interest as microreactors in green or sustainable chemistry.