Association and surface properties of block-copoly-(oxyethylene/oxypropylene/oxyethylene) L64

Abstract

The mode of association of a purified sample of block-copoly(oxyethylene/oxypropylene/oxyethylene) L64 in aqueous solution has been examined as a function of temperature and concentration by surface tension and light-scattering techniques. The association at 34.5 and 40 °C is described by a cooperative association model which assumes aggregate growth by stepwise addition of unimers. Inflections in the curves of surface tension vs. log concentration are shown to be consistent with the concentrations at which enhanced light scattering is first detectable. Only limited association has been detected at 27 °C.