Thermal properties of optically isotropic liquid crystals

光学各向同性液晶的热性质

基本信息

批准号：
11304050
负责人：
SORAI Michio
金额：
$ 25.08万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11304050/
关键词：
Thermotropic liquid crystal Lyotropic liquid crystal Cubic liquid crystal Phase transition Entropy Heat capacity Potically isotropic liquid crystal サーモトピック液晶

项目摘要

1.Heat capacity measurement ofACBC(16)Based on heat capacity rneasurement for a cubic mesogen ACBC(16), we revealed complicoted phasc relationship including newly found crystalline plaases. We also found a glass transition in the new solid phase. The broad heatcapacity anomaly appearing in the isotropic liquid stat was stnpercooed, suggesting that the evct oecurring at the hump be not directly related to the cubictoisotropic liquid phase transition.2. Quasi-binary picture of thermotroplc Iiquid crystalsA quasibinary picture of thermotropic liquid crystals is proposed on the basis of therrnodynantic observations. The conformational entropy of long alkyl chains attached to a (semi)rigid core of mesogenic molecules indicates that the chain is higlaly disordered in liquid crystalline states. These disordered chains seuve as "intramolecular solvenis" or "selfsolvent" judging from a close resemblance between phase diagrams of neat (against chain length) aed binary (against composition) systems. The application of the quasibinary picture to the classic examples of thermotropic cubic mesophases shows that the essential structttral motif is triply periodic minimal surface. This model is not only cousistent witht available experimental restults but also naturally explains smaller heat capacities of cubic mesophases than neighboring liquid crystalline phases.

1. ACBC（16）的热容量测量基于Cutic Mesogen ACBC（16）的热容量RNEASEREMENT（16），我们揭示了复杂的PHASC关系，包括新发现的晶体酶。我们还发现了在新的固相中的玻璃过渡。各向同性液体统计中出现的广泛的热容量异常被刺激，这表明驼峰处的EVCT OECURING与Cubictoisotropic液相相变直接相关。2。嗜热液晶晶体晶体的准二进制图片是基于静态液晶的准晶体图片。长烷基链的构象熵附着在介质分子的（半）刚性核心上，表明该链在液体晶体状态下是链层无序。这些无序的链条将其称为“分子内溶剂”或“自我解决”，从整洁（反对链长）AED二进制（反对组成）系统之间的相似之处的相似之处来判断。准则图片在热旋转立方中间体的经典示例中的应用表明，必需的结构基序是三个周期性的最小表面。该模型不仅与可用的实验恢复相比，而且自然地解释了与邻近的液晶相比，立方中间体的热容量较小。