A FLUORESCENT-PROBE STUDY OF MICELLE-LIKE CLUSTER FORMATION IN AQUEOUS-SOLUTIONS OF HYDROPHOBICALLY MODIFIED POLY(ETHYLENE OXIDE)

Fluorescent probes have been utilized to investigate the micellar natu re of self-association in aqueous solutions of associative thickeners. The specific polymers are C16H33-end-capped urethane-coupled poly(eth ylene oxide)s (HEUR's). Data are presented indicating the presence of micelle-like clusters with two-digit aggregation numbers. The clusters are the building blocks of an association network leading to the form ation of microgels that persist even when the solutions are dilute and of low viscosity. The clusters have a microscopic viscosity far excee ding that of a typical surfactant micelle. Possible consequences of su ch rigid micelles on the interpretation of fluorescence quenching data are discussed and compared with that for surfactant micelles.