Innovative Development of Material Science with Ultra-Sensitive Calorimetory

本研究的主要样品和现象是室温离子液体(RTIL)的相行为。RTIL是一类新的液体，由于其独特的性质和作为功能液体的潜在用途而备受关注。其独特的热行为表现为低熔点、结晶硬度、宽温区预熔、过冷度过大、存在复杂的热历史等。我们使用超灵敏的量热仪、拉曼散射和核磁共振的弛豫时间来测量热量。通过这些实验，我们发现在RTIL的相变过程中出现了特殊的热行为，即“有节奏的熔融和结晶”、“间歇结晶”在预熔区和超低相变。咪唑类化合物的这些独特的热行为归因于组成离子的构象变化和柔性。

The main samples and phenomena of this study are phase behabiors of room-temperature ionic liquids (RTILs). RTILs constitute a new class of liquids that attract much attention because of their characteristic properties and potential utilities as functional liquids. Unique properties are remarkably manifested in their thermal behaviors such as low melting point despite being salts, hardness in crystallization, premelting over a wide temperature range, excessive supercooling, and the existence of complex thermal histories. We performed the measurements of calorimetories using ultra-sensitive calorimeters, Raman scattering and relaxation times of NMR. From these experiments, we found peculiar thermal behaviours at the phase changes of RTILs, namely ‘rhythmic melting and crystallization', ‘intermittent crystallization' in the premelting regions and ultraslow phase changes. These unique thermal behaviours of imidazolium-based RTILs are attributed to conformational changes and flexibility of constituent ions.