液体脆性起源和脆性系数m定量预测理论的实验和理论研究

An understanding of the origin of liquid fragility and a quantitative prediction of the fragility index m is a central issue for understanding the essence of glass formation. These will significantly advance the developments of a wide range of disciplines and technologies. However, such an understanding of the origin of fragility is still lacking. The quantitative prediction of m values, especially the variation of m values with the molar mass of polymers, is a major scientific challenge and has long been known as "dilemma". The breakthrough of this "dilemma" has been severely hindered by the lack of the specific heat capacity data of the polymers with variable molar masses and of typical glass-forming liquids. Therefore, in this program the systematic measurements will be made on the thermal properties (Tg, Cp, and etc.) of different types of polymers with variable molar masses, ionic liquids, highly fragile organic materials and other typical glass-forming liquids, on the variation of the Raman spectra with temperature, and on the low-temperature viscosities and m values of ionic liquids. In addition, the new theoretical equation for prediction of m will be established and systematically tested. The new equations for prediction of the conformation ratio will be developed and then used to predict the "Angell plots" of the studied liquids. This program will furnish a lot of valuable data, the physical origin of fragility and the factors that govern the level of fragility, and the theoretical equation that can provide accurate predictions for the m values of different types of glass-forming liquids and for the variations of the m values with the polymer mass. These results are extremely important for understanding the essence of glass formation and for the developments of a wide range of disciplines and of amorphous materials engineering technologies.

解决液体脆性起源和脆性系数m的预测问题是揭示玻璃态物理本质这一重大科学问题的关键，势必推动众多学科的发展和众多工程技术的进步。但起源问题迄今仍未解决、m特别是聚合物m随其分子量M变化的定量预测仍是颇具挑战性的前沿科学难题，长期被科学界冠以"dilemma"。缺乏Tg时比热（Cp）随聚合物M变化的数据是导致"dilemma"难以突破的重要因素之一。为此，本项目将系统测定（不同M、不同类型）聚合物、离子液体、高脆性有机物等的热性质数据、拉曼光谱随温度的变化、离子液体低温粘度数据和m值。理论方面，将建立m的新理论方程并系统检验、建立典型液体的构象比方程并预测其"Angell plots"。本研究将获取一批珍稀数据、揭示液体脆性起源及控制因素、提供m特别是m随聚合物M变化的定量预测理论。上述研究成果对解决玻璃态本质重大科学问题、对推动众多学科的发展和非晶材料工程技术领域的进步具有极其重要的意义。

系统评价了文献中过冷液体或玻璃体的物性数据，包括Tg数据、过冷液体和玻璃体的m、CP(T)、CP,Tg数据等，给出了推荐值；获取了选定聚合物、小分子有机玻璃形成体、离子熔体、无机网络玻璃形成体的物性数据；合成并测定了选定离子液体和聚合物的物性数据及拉曼光谱；建立了离子液体传递性质的原创性理论Confihuration Exchanging Theory；建立了适于包括聚合物在内的所有类型玻璃体的、可根据分子结构定量预测m的原创性理论方程、打破了著名的“dilemma”；经系统比较，证明了两新理论的预测值与实验数据很好相符；综合比较了m值、“Angell plots” 和拉曼光谱图随温度和分子或离子结构的变化、各种变化趋势的逐一对应关系及对应关系的普适性，定性揭示了脆性起源；根据理论方程参数的物理意义和预测效果，定量揭示了脆性及“Dramatic slow down”的起源和控制因素；上述研究成果对解决玻璃态本质重大科学问题具有十分重要的意义，且可望对凝聚态物理、光学、生物学和聚合物流变学等众多学科的发展起到核心推动作用。. 在J. Chem. Phys., RSC Adv., AIChE J.等期刊上发表和录用了学术论文16篇，还有4篇重要论文已投稿；和张锁江院士等合作出版1部英文专著；申请了5项国家发明专利；是3项省部级奖励(1项技术发明奖特等奖、1项技术发明奖一等奖、1项中国高等学校十大科技进展)的获奖成果之一。