Temperature Dependence of Triton X-100 Micelle Size and Hydration

Abstract

Quasi-elastic light scattering spectroscopy was used to measure the mutual diffusion coefficient, Dm, of Triton X-100 micelles in aqueous solution and the translational diffusion coefficient, DP, of mesoscopic probes in the same solutions. We apply conventional hydrodynamic treatments of diffusion under the assumption that Triton X-100 minimal micelles are adequately represented as hard spheres. Dm and Dp measured at a series of surfactant concentrations are used to infer the micelle radius, am, aggregation number, N, and degree of hydration, δ, for temperatures 10 < T < 50 °C. As T is increased toward the cloud point, am and N increase, the increase in N being especially dramatic above 40 °C, δ at first increases but then tends to saturate with increasing T. © 1995, American Chemical Society. All rights reserved.