An evolution criterion of nonequilibrium thermodynamics and its application to liquid crystals

In thermostatics it is well known that special potentials belonging to discrete systems are extremal, if constraints are given. Aim of this paper is to derive a continuum theoretical foundation of such a variational principle which is also valid in nonequilibrium and which therefore should be denoted as an evolution criterion. Application of this evolution criterion to liquid crystals results in Landau equations in alignment tensor formulation.