Mechanics and Thermodynamics of Curved Thin Films

The basic idea of the micromechanical treatment of nonuniform systems is to consider the pressure as a nonisotropic tensor. The representation of the total pressure tensor as a sum of several terms accounting for different kind of interactions is not unique and it needs some additional model considerations. The concept of disjoining pressure as an additional pressure that must be introduced in the macroscopic theory of thin liquid films was first introduced by Derjaguin and Kusakov. The surface tension of a flat interface does not depend on the location of the Gibbs' dividing surface. The thin liquid film is a nonautonomous system: It is always a part of a larger thermodynamic system, and the processes in the film are governed by the processes occurring in the whole system. The fundamental equations can be valid for not only reversible, but also for some sufficiently slow, irreversible processes.