Odd–Even Effect on Nematic SmAd Phase Boundary and SmAd Structure in Homologous Binary Systems of Cyanobiphenyl Mesogens: 4-Alkyl-4′-cyanobiphenyl (nCB) and 4-Alkoxy-4′-cyanobiphenyl (nOCB)

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• 作者：Yasuhisa Yamamura ; Rei Tsuchiya ; Shuhei Fujimura ; Mafumi Hishida ; Kazuya Saito
• 刊名：Journal of Physical Chemistry B
• 出版年：2017
• 出版时间：February 16, 2017
• 年：2017
• 卷：121
• 期：6
• 页码：1438-1447
• 全文大小：492K
• ISSN：1520-5207

文摘

Phase behaviors of two homologous binary systems of 4-alkyl-4′-cyanobiphenyl (nCB, n being the number of carbon atoms in the alkyl chain) and 4-alkoxy-4′-cyanobiphenyl (nOCB) were investigated. Their phase diagrams were drawn against an averaged chain length, n*. The phase boundary curves between neamtic (N) and smectic A_d (SmA_d) phases in nCB/mCB (n = 3–6; m = 8, 9) binary systems were classified into four depending on four combinations of even- and odd-numbered n and m; even/even, odd/even, even/odd, and odd/odd. The similar odd–even effect was confirmed for nOCB/mOCB (n = 5, 6; m = 8, 9) binary systems. To elucidate the odd–even effect on the phase diagrams, the SmA_d structures were investigated through an analysis of n (n*) dependence of the layer spacing of the SmA_d structure, d_SmAd, of neat nCB (n = 8–10), neat nOCB (n = 8–10), and nCB/8CB (n = 0–7) binary mixtures. The odd–even effect, the behavior of 0CB/8CB system, and the difference between nCB and nOCB were clarified based on their SmA_d structures.