Theory of the orientational transitions in lyotropic liquid crystals: "twist-and-glide" states

A phenomenological theory that describes the reorientational phase transiti ons between inhomogeneous states in lyotropic liquid crystals in an externa l magnetic field is presented. The specific properties of lyotropic liquid crystals - the biaxial surface layer formation and the rotation of the surf ace director due to the gliding of the micelles - are taken into account. T he equilibrium phases are characterized by the orientation of the "gliding" director in the biaxial surface layer with respect to the bulk director. A n optical transmission experiment is proposed to show experimental evidence for the reorientational transitions in lyotropic liquid crystals. (C) 1999 Elsevier Science B.V. All rights reserved.