Onsager Variational Principle in Soft Matter Physics

Abstract

We introduce Onsager variational principle for the derivation of the kinetic equations of purely dissipative systems in the level of Stokesian hydrodynamics. As many soft matter systems belong to this class, the principle can thus be used in the study of soft matter dynamics. In this article, a brief connection between the particles and the thermodynamic systems is presented. We discuss the reciprocal relation which is the important concept of the principle. The relation allows us to write the frictional force in a similar manner of determining the potential force from the gradient of the potential energy. The simplest application of the principle for solving the problem in soft matter dynamics is also shown.