A simple molecular theory of smectic C liquid crystals

In the previous chapters we have described several novel phase transitions exhibited by compounds with molecules having longitudinal components of permanent electric dipole moments. As described in Chapter-1, in the smectic C (SmC) phase, the constituent molecules are tilted in the smectic layers. The SmC liquid crystal is made of compounds with molecules having lateral components of dipole moments. There are many reports in the early literature on the synthesis of compounds that were later found to exhibit the SmC phase [1]. However, the SmC phase was given the designation originally by Sackmann and Demus [2] based on the miscibility studies and the observation of textures. In this chapter, we discuss the molecular origin of tilt in the SmC liquid crystals and develop a molecular theory of phase transitions involving SmC liquid crystals.