A novel epoxide monomer, 1,3-didodecyloxy-2-glycidyl-glycerol (DDGG), bearing an aliphatic double chain was prepared. DDGG was anionically homopolymerized and block copolymerized with ethylene oxide (EO). The polymers were characterized by H-1 nuclear magnetic resonance spectroscopy, gel permeation chromatography, vapor pressure osmometry, and differential scanning calorimetry. The decrease in transmittance of the aqueous solutions of the copolymer, denoted EO(115)DDGG(2), With raising temperature and/or concentration was attributed to the presence of aggregates. An anomalous increase in the transmittance at 35 degreesC was noted as well. A dye solubilization method was used to demonstrate the ability of EO(115)DDGG(2) to associate in aqueous solution. The associative interactions gave rise to a sharp increase in viscosity. (C) 2001 Elsevier Science Ltd. All rights reserved.