Synthesis of Thermoresponsive Polyurethane from 2‐Methylaziridine and Supercritical Carbon Dioxide

Under pressure: Temperature-dependent optical transmission in aqueous solution is exhibited by polyurethanes that are obtained by copolymerization of 2-methylaziridine and supercritical CO2 (scCO2; see scheme). The transmittance drops sharply at the lower critical solution temperature (LCST). The molecular weight, content of urethane linkages, and LCST value of the polyurethanes are controllable simply by changing the CO2 pressure.