Layer compression modulus of the antiferroelectric liquid crystal MHPBC

Abstract The layer compression modulus B was determined near the smectic-A-smectic-Cα* phase transition in an antiferroelectric liquid crystal 4-(l-methylheptyloxycarbonyl)-phenyl 4′-octylbiphenyl-4-carboxylate (MHPBC). The temperature dependence of B clearly defined the smectic-A-smectic-Cα* phase transition temperature and supplied a new and clear evidence that the smectic-Cα* phase is a tilted phase. The pretransitional softening of B can be represented by a simple power law and explained well by the theoretical description based on renormalization-group method. These results clearly show that the transition is not of the Landau mean-field type.