Micellisation and surface properties of poly(oxyethylene) alkyl ethers

Abstract

A series of poly(oxyethylene) alkyl ethers, of general formula CH₃O(CH₂CH₂O)₂₇(CH₂)_n H with n in the range 12–23, has been prepared. Surface-tension measurements over a range of concentrations and temperatures have been used to investigate the micellisation and surface properties of the ethers in aqueous solution. At concentrations just below the critical micelle concentration (c.m.c.) the area per molecule in the surface monolayer corresponds to that of an alkyl chain lying flat on the surface. The decrease in log (c.m.c.) with increase in n is non-linear at high n. The temperature dependence of the c.m.c. is in accord with the hydrophobic effect.