冰晶模板组装技术中通过热力学因素调控气凝胶微观结构与性能的机理研究

How to regulate the aerogel microstructure is one of the most important and basic scientific problems in the field of aerogel materials. Ice crystal template is a simple and green method to prepare aerogels. In recent years, the microstructure of aerogels has been regulated by the dynamics of ice crystal growth. However, it is often neglected to regulate the microstructure from the thermodynamic aspects due to the lack of interdisciplinary knowledge. In this project, we propose to systematically study the influence of thermodynamic properties of different aerogel precursor systems on the nucleation and growth of ice crystals, and then control the aerogel microstructure. Furthermore, we will investigate the relationship between the design of precursor system, ice crystal structure, aerogel microstructure and mechanical / thermal conductivity. We plan to study (1) the construction of typical aerogel precursor model systems; (2) the physical and chemical properties and morphology of ice in the aerogel precursor model systems; (3) effects of ice crystal structure and morphology on the structure and properties of aerogels. This project involves the knowledge of physical chemistry, polymer physics, crystallography and colloidal physics. The outcomes of this project will provide scientific basis for the design of aerogel precursor systems and the regulation of aerogel microstructure.

如何定构气凝胶的微观结构是气凝胶材料领域最重要和最基础的科学问题之一。冰晶模板法是一种简单绿色的制备气凝胶的方法。近年来通过控制冰晶生长的动力学条件调控气凝胶的微观结构取得了较大的研究进展；然而，由于涉及学科交叉，从热力学角度调控气凝胶的微观结构往往被忽视。本项目提出系统地改变冰晶模板法中气凝胶前驱体体系的热力学性质，研究热力学性质对冰晶成核与生长的影响规律，进而实现气凝胶微观结构的定构，旨在建立前驱体体系设计—冰晶结构—气凝胶微观结构—力学/导热性能的关系。主要研究内容包括：（1）典型气凝胶前驱体模型体系的构筑；（2）气凝胶前驱体模型体系中冰的物理化学和形态结构研究；（3）冰晶结构和形貌对气凝胶结构和性能的影响。本项目涉及物理化学、高分子物理、晶体学和胶体物理等学科交叉，项目的开展将为从热力学角度进行气凝胶前驱体体系的设计和气凝胶微观结构的调控提供科学依据，具有重要理论价值和现实意义。

如何构筑气凝胶的微观结构、性能和功能是气凝胶材料领域最重要和最基础的科学问题之一。我们通过控制冰晶生长的动力学条件调控聚电解质水溶液、氧化石墨烯悬浮液和氧化石墨烯悬浮液/添加剂三类气凝胶前驱体，揭示溶质和分散相的存在对水的表面张力、相变温度、相变和临界成核等性能的研究。通过气凝胶前驱体模型体系中水的物理化学性质和冰晶结构，认识了前驱体体系中水的热力学变化对冰核的形成和生长行为的影响；离析模型体系中冰晶的形态结构与气凝胶微观结构的关系，指导制备微观形貌可控的多孔气凝胶材料。通过研究高性能、低热导率气凝胶的前驱体体系的设计，回答了前驱体体系水冰物理化学性质对气凝胶微观结构的影响机制；弄清前驱体体系—冰晶形态结构—气凝胶微观结构—气凝胶力学性能/导热性能/功能化的关系，制备了一系列高性能的气凝胶，本项目从热力学角度进行气凝胶前驱体体系的设计和气凝胶微观结构的调控提供科学依据，具有重要理论价值和现实意义。