Amphiphilic polyurethane was synthesised. It shows greater surface activity than that of sodium dodecyl sulfate and can form micelles in water. The mean aggregation number of polyurethane micelles was small on account of the multiple headgroups of the monomeric chain and the coiled polyoxyethylene chains. The micelle interior provides comfortable microenvironment to hydrophobic solutes. The negative free energy of transfer suggests the spontaneous tendency for solute to transfer from the aqueous phase into the micellar pseudophase. Partition coefficient and binding constant are proved to be independent of solute concentration. (C) 2010 Elsevier B.V. All rights reserved.