UCST behavior of polyampholytes based on stoichiometric RAFT copolymerization of cationic and anionic monomers.

Polyampholytes with controlled equimolar ratio of charges were synthesized by reversible addition-fragmentation chain transfer (RAFT) copolymerization of cationic and anionic monomers. The resulting charge-neutral polyampholytes exhibit upper critical solution temperature (UCST) thermoresponsive behavior in ethanol-water and methanol-water solvent mixtures based on electrostatic attraction. Finally, the temperature induced self-assembly of a polyampholyte with oligo(ethylene glycol) side chains into defined nanoparticles below the UCST transition is demonstrated.