AGGREGATION BEHAVIOR OF HEXAOXYETHYLENEGLYCOL MYRISTATE AND HEXAOXYETHYLENEGLYCOL MONO(1-METHYLTRIDECANE) ETHER AND DYNAMICS OF THEIR MICELLES IN AQUEOUS-SOLUTION

The title surfactants have similar critical micelle concentrations and cloud temperatures. Their micellar solutions have been investigated by time resolved fluorescence quenching in the range 2-25°C. The micelle aggregation numbers of both surfactants do not differ much, and increase with temperature. Aggregation numbers are large, suggesting anisotropic micelles, and the results show that the micelles are polydisperse. Fast intermicellar exchange of material becomes detectable on the fluorescence timescale (˜ 1 μs) above T ≈ 10°C, i.e., some 35-40°C below the cloud temperature of the solution. This exchange probably occurs via micelle collisions with temporary merging. Overall the behavior of these two surfactants is very similar to that of the other ethoxylated nonionic surfactants previously examined. © 1993 by Academic Press, Inc.