Alternative approach to the design of thermosensitive polymers: The addition of hydrophobic groups to the ends of hydrophilic polyether

We synthesized thermosensitive polymers by adding Hydrophobic groups to the ends of a hydrophilic polyether, poly(ethylene oxide-co-propylene oxide). The cloud points of the polymers were controlled by the molecular weight of the polyether and the kind of hydrophobic end group. The polymers showed relatively sharp phase transitions, as observed by turbidimetry. The order of the cloud points of the polymers with various end groups did not follow that of the critical micelle concentrations of the polymers determined with fluorescence measurements with pyrene as a probe. The cloud points of the polymers linearly decreased with increasing concentrations of salts (Na₂SO₄ and Na₃PO₄). The slopes of the linear lines were almost constant, regardless of the kind of hydrophobic group and the molecular weight of the polyether.