A theory of melting in liquid crystals

Abstract A dislocation theory of melting is proposed to explain the smectic B to smectic A phase transition observed in liquid crystals. Besides providing a good description of the quasi-two-dimensional smectic phases, it establishes a new theoretical connection between the transition temperature and the elastic constants, as well as predicting the latent heat. We suggest that the finite shear viscosity of the smectic A phase may be understood in terms of the existence of thermodynamically stable isolated dislocations in the layer periodicity.