The diffusion of monodisperse polystyrene latex of 910 Å diameter through Millipore filters containing pores from 2200 to 12000 Å has been measured at 25° and 45°C. The temperature dependence of the diffusion coefficient and the variation of diffusion coefficient with pore diameter are consistent with the model of a rigid sphere surrounded by a continuum and moving in a cylindrical pore. However, the diffusion coefficients are roughly ten times those predicted by the Stokes-Einstein equation-an effect apparently caused by the high surface charge resulting from adsorbed soap ions.
Bibliographical noteFunding Information:
teachers for a summer fellowship; E. L. Cussler is grateful for a Ford Foundation Research Fellowship.