Thermodynamic model to study the ferroelectric behaviour of lactic acid derivatives with keto linkage group

ABSTRACT

The electro-optical and structural properties of chiral lactic acid derivatives with keto linkage group ((S)-4-((1-alkoxy-1-oxopropan-2-yloxy) carbonyl)phenyl4’-alkyloylbiphenyl-4-carboxylates denoted as KL n/m) exhibiting Sm C* phase and Sm A*−Sm C* phase transition have been studied by using a thermodynamic model based on Landau-de-Gennes theory. The free-energy density of the system is expanded in terms of three degrees of freedom – tensor orientational order $Q_{ij}$, the scalar smectic order $\psi$, the polarisation vector P, the wave vector q, and the couplings between these order parameters. The values of the Landau coefficients involved in the free-energy density have been calculated by comparing the experimental data of tilt angle, spontaneous polarisation, and pitch of KL n/m. The theoretical and experimental data have been analysed, and a close agreement has been found between the two.

KEYWORDS:

• Thermodynamic model
• ferroelectric liquid crystals
• phase transition properties
• Landau-de-Gennes Theory

Acknowledgement

The author would like to acknowledge JSSMVP Mysore for the kind support and encouragement.

Disclosure statement

No potential conflict of interest was reported by the author(s).