Thermal properties of optically isotropic liquid crystals

光学各向同性液晶的热性质

• 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

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)的热容测量基于立方介晶ACBC(16)的热容测量，我们揭示了包括新发现的结晶相在内的复杂相关系。我们还在新固相中发现了玻璃化转变。各向同性液体状态中出现的广泛热容异常得到了证实，表明驼峰处发生的evct与立方各向同性液体相变没有直接关系。 2．热致液晶的准二元图根据热力学观察提出了热致液晶的准二元图。连接到介晶分子的（半）刚性核心的长烷基链的构象熵表明该链在液晶状态下是高度无序的。从纯（相对于链长）和二元（相对于组成）系统的相图之间的密切相似性来看，这些无序链被视为“分子内溶剂”或“自溶剂”。准二元图像在热致立方中间相的经典例子中的应用表明，基本的结构图案是三周期最小表面。该模型不仅与现有的实验结果一致，而且自然地解释了立方中间相比邻近液晶相更小的热容。

项目成果

K.Saito: "Degree of disorder in cubic mesophases in thermotropics : Thermodynamic study of a liquid crystal showing two cubic mesophases"Physical Review E. 65. 031719 (2002)

K.Saito：“热致材料中立方中间相的无序度：显示两个立方中间相的液晶的热力学研究”物理评论 E. 65. 031719 (2002)

K, Saito, T, Shinhara, T, Nakamoto, S, Kutsumizu, S, Yano, M, Sorai: "Degree of disorder in cubic mesophases in thermotropics: Thermodynamic study of a liquid crystal showing two cubic mesophases"Phys. Rev. E. 65. 031719 (2002)

K、Saito、T、Shinhara、T、Nakamoto、S、Kutsumizu、S、Yano、M、Sorai：“热致立方中间相的无序度：显示两个立方中间相的液晶的热力学研究”Phys。

S, Asahina, M, Sorai: "Thermodynamic properties of discotic of discotic mesogens: Heat capacities and phase trasitions of benzene-hexa-n-alkanoates"J. Chem. Thermodynamics. 35. 641-658 (2003)

S、Asahina、M、Sorai：“盘状介晶的热力学性质：苯-六正烷酸酯的热容量和相变”J。

K.Saito: "Degree of disorder in cubic mesophases in thermotropics : Thermodynamic study of a liquid crystal showing two cubic mesophases"Physical Review E. 65(3). 031719 (2002)

K.Saito：“热致材料中立方中间相的无序度：显示两个立方中间相的液晶的热力学研究”物理评论 E. 65(3)。

M, Sorai, K, Saito: "Alkyl chains acting as entropy reservoir in liquid crystallinc materials"Chem. Rec.. 3. 29-39 (2003)

M、Sorai、K、Saito：“烷基链在液晶材料中充当熵库”Chem。