Nonequilibrium Thermodynamics of Colloids

The common rules of classical nonequilibrium thermodynamics do not allow an Onsager coefficient like the viscosity to depend on the shear rate. Such a dependence is experimentally well documented, however. In this paper it is shown, using nonequilibrium thermodynamics alone, how it is possible that the effective viscosity coefficient of an isotropic colloidal system depends on both the shear rate and the frequency.