Temperature Dependence of the Tilt Angle for the Smectic A-Smectic C∗ Transition in a Mixture of C7-70PDOB Ferroelectric Liquid Crystals near the Tricritical Point

Abstract EN

The temperature dependence of the tilt angle θ is studied in the smectic C∗ phase near the smectic A-smectic C∗ tricritical point for a mixture of 70PD0B in the ferroelectric liquid crystal C7 (X=16.92).

The mean-field models with the biquadratic P2θ2 (P is the spontaneous polarization) and P2θ2+Pθ (bilinear) coupling terms in the free energy expansion are used to analyze the experimental data for the tilt angle in this binary mixture.

From our analysis, the coefficients given in the free energy expansion of the mean-field models are determined.

Our results show that the mean-field theory explains adequately the observed behaviour of the C7-70PD0B mixture near the AC∗ tricritical point.