Specific heats of nematic, smectic, and cholesteric liquid crystals by differential scanning calorimetry
Specific heats of nematic, smectic, and cholesteric liquid crystals by differential scanning calorimetry
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通过差示扫描量热法测定向列液晶、近晶液晶和胆甾液晶的比热
DOI：
10.1021/j100863a018
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发表时间：
1967
期刊：
影响因子：
--
通讯作者：
Julian F. Johnson
中科院分区：
文献类型：
--
作者：
E. Barrall;R. Porter;Julian F. Johnson
差示扫描量热法已被应用于三种具有液晶或中间相行为的纯化合物的研究。这些化合物是对氮杂环己烷、樟柳碱和肉豆蔻酸胆固醇。前两种化合物显示单一的向列型中间相，后一种化合物同时形成近晶型和胆甾型中间相。因此，三种基本类型的中间相在这项比热研究中得到了评价。测量了结晶固体、中间相和相应的各向同性液体的温度范围。还测量了过冷相和接近一级中间相转变的温度下的比热。对偶氮苯甲醚的测量结果与以前的文献值吻合较好。到目前为止，还没有关于胆固醇酯的比热测量。对三种基本中间相类型的结果进行了相互比较。
Differential scanning calorimetry has been applied to the study of three pure compounds exhibiting liquid crystal or mesophase behavior. The compounds were p-azoxyanisóle, anisaldazine, and cholesteryl myristate. The first two compounds exhibit a single meso-phase of the nematic type, and the last compound forms both a smectic and a cholesteric-type mesophase. The three basic types of mesophases are thus evaluated in this study of specific heats. Measurements were made in the temperature ranges for the crystalline solid, the mesophase, and the corresponding isotropic liquid. Specific heats were also measured on supercooled phases and at temperatures close tothe first-order mesophase transitions. The measurements on p-azoxyanisole compare well with previous literature values. Specific heat measurements on cholesteryl esters have not been presented here-tofore. The results on the three basicmesophase types are intercompared.