Biaxial order parameter in the homologous series of orthogonal bent-core smectic liquid crystals

Sreenilayam, S. and Panarin, Y.P. and Vij, J.K. and Osipov, Mikhail and Lehmann, A. and Tschierske, C. (2013) Biaxial order parameter in the homologous series of orthogonal bent-core smectic liquid crystals. Physical Review E, 88 (1). 012504. ISSN 1539-3755

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    Abstract

    The fundamental parameter of the uniaxial liquid crystalline state that governs nearly all of its physical properties is the primary orientational order parameter (S) for the long axes of molecules with respect to the director. The biaxial liquid crystals (LCs) possess biaxial order parameters depending on the phase symmetry of the system. In this paper we show that in the first approximation a biaxial orthogonal smectic phase can be described by two primary order parameters: S for the long axes and C for the ordering of the short axes of molecules. The temperature dependencies of S and C are obtained by the Haller's extrapolation technique through measurements of the optical birefringence and biaxiality on a nontilted polar antiferroelectric (Sm-APA) phase of a homologous series of LCs built from the bent-core achiral molecules. For such a biaxial smectic phase both S and C, particularly the temperature dependency of the latter, are being experimentally determined. Results show that S in the orthogonal smectic phase composed of bent cores is higher than in Sm-A calamatic LCs and C is also significantly large.

    ORCID iDs

    Sreenilayam, S., Panarin, Y.P., Vij, J.K., Osipov, Mikhail ORCID logoORCID: https://orcid.org/0000-0002-1836-1854, Lehmann, A. and Tschierske, C.;