A new series of thermo-sensitive polyethers were prepared by anionic ring-opening polymerization of glycidyl ether derivatives: glycidyl methyl ether, ethyl glycidyl ether, and ethoxyethyl glycidyl ether. The prepared polymers have controllable molecular weight with narrow molecular weight distributions. These polymers exhibit a lower critical solution temperature (LCST) in water. The LCST is altered from 14.6 to 57.7degreesC by decreasing the hydrophobicity of the side-chain units.