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The European Physical Journal B
ISSN: 1434-6028 (printed version)
ISSN: 1434-6036 (electronic version)
Abstract Volume 5 Issue 4 (1998) pp 835-838
rapid note: Smectic A-Cholesteric liquid crystal phase transition: A density study
E.L. Duarte (1)(2), A.J. Palangana (1) (a), R. Itri (2), A.R. Sampaio (1), A.A. Barbosa (1)
(1) Departamento de Física,Universidade Estadual de Maringá, 87020-900 Maringá, Paraná, Brazil
(2) Instituto de Física, Universidade de S ao Paulo, Caixa Postal 66318, 05315-970 S ao Paulo, Brazil
Received: 25 May 1998 / Revised: 27 July 1998 / Accepted: 7 August 1998
Abstract: The present work is focused on density measurements near the smectic A-cholesteric liquid crystal phase transition for cholesteryl myristate $(\rm C_{14})$, cholesteryl nonanoate $(\rm C_9)$ and binary mixtures of $\rm C_{14}$ and $\rm C_9$ and cholesteryl caproate $(\rm C_6)$ and $\rm C_9$. The results have evidenced that the transition crosses over from first to second order when both the mean molecular length and the reduced temperature, r (ratio between the smectic A-cholesteric and cholesteric-isotropic phase transition temperatures), decrease in the system. The occurrence of a second order phase transition is observed for a concentration very near 63.1 molar percent of $\rm C_9$ in the $\rm C_6{-}C_9$ mixture at r $\cong 0.92$.
PACS. 61.30.Eb Experimental determinations of smectic, nematic, cholesteric, and other structures - 64.70.Md Transitions in liquid crystals
(a) email: palanga@dfi.uem.br
Article in PDF format (245 KB)
Online publication: October 29, 1998
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