Thermodynamic model to study the structural and electro-optical properties of chiral antiferroelectric smectic C phase exhibited by mesogenic homologous series 3FnHBM6(s) and W-316 mixture.

Using a thermodynamic model developed by us to study the structural and electro-optical properties of ${\rm Sm\; C}_{\rm A}^{\rm \ast }$ Sm C A ∗ phase, we investigate the temperature dependence of helical pitch, tilt angle and spontaneous polarization of a homologous series of fluorinated biphenyl benzoate esters (3FnHBM6, n = 2, 5, 7) and one of the series W-316-3 obtained from the mixture of two chiral liquid crystalline compounds 6F2OBi and 3F6HBM6. The free-energy density of the system exhibiting ${\rm Sm\; C}_{\rm A}^{\rm \ast }$ Sm C A ∗ phase is written as an expansion series in terms of all the relevant degrees of freedom: ${\bf Q}_{{\bf ij}}$ Q i j , ψ, P, q and the resulting coupling terms between these order parameters. The values of Landau coefficients are determined from the experimental data of antiferroelectric mesogens 3FnHBM6 (n = 2, 5, 7) and W-316-3 in the ${\rm Sm}\; {\rm C}_{\rm A}^{\rm \ast }$ Sm C A ∗ phase. Using these coefficients, the electro-optical and structural properties have been studied. We have found good agreements between the theoretical and experimental results. [ABSTRACT FROM AUTHOR]