【摘要】 以季戊四醇为中心,4-(正烷基酰氧基)-4′-苯甲酰氧基苯甲酸为液晶臂,经酯化反应合成一种芳香酯类星型四臂液晶化合物。通过元素分析、红外光谱、核磁共振谱测试技术对其分子结构进行表征。采用差示扫描量热、偏光显微分析、X射线衍射分析等测试技术对其液晶相行为进行研究。结果表明,随着端基柔性链的加长,tm、ti、tic及tc呈降低趋势,它们在液晶态时均呈现破碎焦锥及焦锥织构,属互变近晶相液晶,液晶区间较宽。其中升温时D1～D4的tm和ti值分别为92．3、80．6、68．3、51．1和159．2、145．1、127．5、109．8℃,液晶范围△t1在66．9～58．7℃之间,降温时的tic和tc值分别为138．6、127．4、111．6、99．1和57．1、52．6、42．0、31．8℃,液晶范围△t2在81．5～67．3℃之间。更多还原

【Abstract】 A new class of star-shaped four-armed liquid crystals based on pentaerythritol as a flexible core was synthesized by aromatic esterification. Their chemical structures were confirmed by means of elemental analysis, IR and 1H NMR characterizations, their mesomorphic properties and phase behavior were investigated by differential scanning calorimetry, polarizing optical microscopy and X-ray diffraction. The results show that tm, ti, tic and tc decreases as the carbon chain of the terminal groups increases. They displayed broken focal-conic and focal-conic texture in liquid crystal states, and had a wide mesophase temperature range. The tm and ti of D1～D4 were 92. 3℃, 80. 6℃, 68. 3℃, 51. 1℃and 159. 2℃, 145. 1℃, 127. 5℃, 109. 8℃respectively, the mesogenic region△t1 decreased from 66. 9℃to 58. 7℃; while the tic and tc were 138. 6℃, 127.4℃, 111. 6℃, 99. 1℃and 57. 1℃, 52. 6℃, 42. 0℃, 31. 8℃respectively, the mesogenic region△t2 decreased from 81. 5 t to 67. 3℃.更多还原