Physical Properties of Nematic Tolans
Physical Properties of Nematic Tolans
复制标题
向列型托兰的物理性质
DOI：
10.1080/00268948608079615
复制
发表时间：
1986
影响因子：
0.7
通讯作者：
M. Sasaki
中科院分区：
文献类型：
--
作者：
H. Takatsu;K. Takeuchi;Y. Tanaka;M. Sasaki
合成了一系列4-正烷基-4 ′-正烷氧基二苯乙炔、反式-4-正烷基环己基-4 ′-正烷基二苯乙炔和4-正烷基-2 ′-或3′-取代的4′-正烷氧基二苯乙炔。测量了它们的介晶和物理性质。制备了4-n-烷基-4 ′-n-烷氧基-二苯乙炔的混合物和其它常见的以n-烷基和n-烷氧基为端基的双环体系的混合物，并比较了它们的物理性能。二苯乙炔的混合物具有72 ℃的高N-I转变温度、0.297的高双折射率和在20 ℃下19. 1c. p.的低粘度。用外推法测定了反式-4-正丙基环己基-4 ′-正丁基二苯乙炔的双折射率和流动取向粘度，并与反式-4-正戊基环己基-4 ′-乙基联苯和4-正丙基苯基-4 ′-正丙基环己基苯甲酸酯的双折射率和流动取向粘度进行了比较。讨论了在4-n-烷基-4 ′-n-烷氧基二苯乙炔中引入2′-，3′-氟和2′-，3 ′-甲基对介电常数的影响。
Abstract A series of 4-n-alkyl-4′-n-alkoxytolans, trans-4-n-alkylcyclohexyl-4′-n-alkyltolans and 4-n-alkyl-2′- or 3′-substituted 4′-n-alkoxytolans was prepared. Their mesomorphic and physical properties were measured. Some nematic mixtures of 4-n-alkyl-4′-n-alkoxy-tolans and other familiar series of nematic mixtures of two-ring systems having n-alkyl and n-alkoxy as terminal groups were prepared and their physical properties were compared. A nematic mixture of tolans has a high N-I transition temperature of 72[ddot]C, a high birefringence of 0.297 and a low viscosity of 19.1 c.p. at 20[ddot]C. The birefringence and the flow-aligned viscosity of trans-4-n-propylcyclohexyl-4′-n-butyltolan were determined by extrapolation and compared with those of trans-4-n-pentylcyclohexyl-4′-ethylbiphenyl and 4-n-propylphenyl 4′-n-propylcyclohexyl-benzoate. The influence of the introduction of 2′-, 3′-fluoro and 2′-, 3’ -methyl groups into 4-n-alkyl-4′-n-alkoxytolans on the dielectric constants was discussed.