Affiliation:
1. Department of Physics and Astronomy, University of Manchester
2. Institute of Physics, Experimental Physics Department, University of São Paulo
Abstract
Abstract
In this chapter we will revise some basic aspects of the Onsager and the Landau–de Gennes theories to describe the nematic to isotropic and nematic to nematic phase transitions. These theories are mean-field theories and catch the main physical aspects of these transitions. The topology of the phase diagrams of micellar lyotropic nematic liquid crystals is presented. In particular, the need of a non-critical order parameter is discussed, to account for the presence of the biaxial nematic phase between the two uniaxial phases. It is not our aim here to repeat the mathematical calculations of these theories, since there is a good bibliography about them. In particular, good books can be consulted by readers with detailed descriptions of these theories and extensive bibliography.
Publisher
Oxford University PressOxford