Transport Coefficients Near the Consolute Temperature of a Binary Liquid Mixture

Abstract

Transport coefficients are computed near the critical mixing point of a classical binary liquid mixture by considering processes in which one transport mode breaks up into several. The conclusions are that, when the concentration has its critical value and the temperature is near the consolute temperature, the diffusion coefficient does not go to zero as fast as ${(\frac{\ensuremath{\partial}{\ensuremath{\mu}}_{12}}{\ensuremath{\partial}x})}_{P,T}$, but only as fast as ${\ensuremath{\xi}}^{\ensuremath{-}1}\ensuremath{\approx}{|T\ensuremath{-}{T}_{C}|}^{\frac{2}{3}}$, where $\ensuremath{\xi}$ is the temperature-dependent coherence length; that the shear viscosity has at most a logarithmic divergence; that the thermal diffusion coefficient has at most a very weak divergence; and that the thermal conductivity has no divergent part. A result very similar to that of Kawasaki and Tanaka is found for the bulk viscosity.