Functional sulfobetaine polymers: Synthesis and salt-responsive stabilization of oil-in-water droplets

Novel zwitterionic sulfobetaine polymers were synthesized, featuring alkene and alkyne groups embedded directly into the zwitterionic subunits. Alkene and alkyne versions of 1,3-propane sultone afforded access to functional zwitterionic methacrylates, which proved amenable to controlled free radical polymerization and copolymerization. These functional variants of polymer zwitterions exhibited desirable salt-responsive behavior characteristic of many polymer zwitterions, in which salt screened electrostatic interactions and resulted in droplet coalescence. Moreover, the presence of unsaturated groups in these polymers opens routes to facile chemistry at fluid-fluid interfaces and the preparation of robust polymer capsules.