Synthesis of pH-responsive Micelle by RAFT

摘要

Recent efforts in our group have focused on the synthesis of polymeric surfactants to serve as unimeric micelles for oil spill remediation applications. Previously, we have prepared anionic amphiphilic copolymers ("polysoaps") via reversible addition-fragmentation chain transfer (RAFT) polymerization which allowed for molecular weight control and narrow molecular weight distributions. Initial studies have shown that polysoaps prepared from hydrophobic dodecyl acrylamide and hydrophilic AMPS monomers form micelles in water that can sequester hydrophobic, organic molecules. Also, we have recently synthesized sulfonamide-containing homopolymers by RAFT polymerization that exhibit changes in aqueous solubility in response to hexyl-phenyl methylacrylamide as the hydrophobic monomer. By varying the composition and structure of the hydrophobic/hydrophilic monomers incorporated into the polysoaps, the behavioral properties and CO_2 dependence of the micelle formation and precipitation can be determined. The conceptual aspects of this approach, as well as the synthesis, characterization and behavioral properties of micelle formation and precipitation will be a CO_2 stimulus. Upon purging with CO_2 these homopolymers become water insoluble and result in polymer precipitation or phase separation. By incorporating functional sulfonamides into a well-defined polysoap backbone, a CO_2 responsive polysoap may be prepared and potentially used for advanced oil recovery in open sea water. Current efforts are being explored to develop these types of responsive polysoaps using sulfonamides as the hydrophilic monomer and 4- discussed.