Design of temperature-responsive polymers with enhanced hysteresis: alpha,alpha-disubstituted vinyl polymers.

Three temperature-responsive polymers which are alpha,alpha-disubstituted vinyl polymers having two amphiphilic groups (ethylamide or ethylester) per monomeric unit were designed. Two of these polymers showed unusually large hysteresis in their phase transition temperatures between a heating and a cooling process. This hysteresis resulted from the extremely slow kinetics of the dissolution process of the aggregated polymer chains in the cooling process due to intra- and interchain interactions including hydrogen bonding and hydrophobic interaction.