Weak anchoring resolved substrate interface and bulk mode processes in surface stabilized ferroelectric liquid crystal

Abstract

Abstract Dielectric spectroscopy is employed to investigate the behaviour of bulk mode (phason mode, or Goldstone mode (GM) in ferroelectric liquid crystals (FLCs)) and surface phenomenon (partially unwound helical mode) in surface stabilized FLC (SSFLC) sample cells. The surface effect influences the basic characteristic of GM phenomenon to a great extent, even if the surface anchoring energy of the cell is kept very weak. The effect of different measuring and bias fields on the GM and surface processes has been studied in smectic C* (SmC*) phase and also at transition temperature (Tc (SmC* to SmA*)) of SmC* and smectic A* (SmA*) phases. It has been observed that in surface stabilized geometry, there exists two molecular dynamics: one near the surface of the electrodes and another in the bulk of the cell which contributes separately in the dielectric properties. The phason mode is also observed at Tc (SmC* to SmA*) and a few degrees above Tc (SmC* to SmA*) i.e. in SmA* phase of FLC in thin cell of surface stabilized geometry. The application of weak and medium measuring electric fields reverses the varying trend of GM frequency process at the phase transition from SmC* to SmA* phase. The study is intended to explore the surface effect along with the surface and bulk interface that influence the bulk response in SSFLC state.