STRONG CRITICAL ENHANCEMENT OF THE SHEAR VISCOSITY OF COLLOIDAL SYSTEMS

The critical divergence of the shear viscosity of a colloid polymer mi xture is experimentally round to be as strong as the divergence of the correlation length. This is in contrast with the divergence of the vi scosity in atomic and molecular systems, which is known to be very wea k. The different behavior of the shear viscosity of Brownian systems a nd molecular systems is believed to be due to die long ranged characte r of the hydrodynamic interactions between the Brownian particles, a t ype of interaction absent in molecular systems.