Nj. Mottram et Sj. Elston, Order parameter theory of the pre-transitional behaviour in antiferroelectric liquid crystals, LIQ CRYST, 26(3), 1999, pp. 457-464
We propose an order parameter theory as a possible description of the pre-s
witching behaviour of antiferroelectric liquid crystals (AFLCs). Assuming t
hat the antiferroelectric state is preserved so that the directors in adjac
ent layers ape on opposite sides of the smectic cone, we consider changes i
n the molecular order about these directors. Our theory incorporates interl
ayer and intralayer dipole-dipole interactions, the dipole-electric field i
nteraction and the thermodynamic potential. The effective optic axis as a f
unction of applied voltage can then be calculated and is found to be in qua
litative agreement with experimental observations which show a superlinear
dependence.