Polymorphism of Chiral Thioester Studied by Dielectric Spectroscopy

A.I. Wawrzyniaka, J. Chruścielb, R. Doualic, F. Duboisc, J.-M. Leblondc, Ch. Legrandc, D.M. Ossowska-Chruścielb, M. Marzeca, P. Ropac, J.M. Czerwieca and S. Wróbela aJagiellonian University, Institute of Physics, W.S. Reymonta 4, 30-059 Kraków, Poland bInstitute of Chemistry, Siedlce University of Natural Sciences and Humanities, 3-go Maja 54, 08-110 Siedlce, Poland cUniversité du Littoral Côte d'Opale, 50 rue F. Buisson, B.P. 717, 62228 Calais, France

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(S)-(+)-4'-[(4-(1-methylheptyloxycarbonylphenyl) thiocarbonylphenyl]-decyloxybenzoate (in short 10.OPOSMH) was studied by complementary methods. The substance shows rich polymorphism. In addition to ferroelectric and antiferroelectric smectic C* phases it possesses three ferrielectric sub-phases. Phase transitions between the phases were revealed by differential scanning calorimetry and static dielectric permittivity measurements. The aim of this paper was to study phase transitions and differences in dielectric spectra shown by different phases. Collective and molecular dynamics of all phases shown by 10.OPOSMH will be discussed in terms of theoretical models. Dielectric spectra of antiferroelectric phase show two characteristic dielectric relaxation modes: one connected with the molecular process (reorientation around the short axis) and the other originating from fluctuations of antiferroelectric order parameters.

DOI: 10.12693/APhysPolA.124.933 PACS numbers: 77.84.Nh, 64.70.M-, 77.22.Gm, 77.22.Ej