定向层状氧化铝气凝胶的构筑机理及其复合材料的热管理调控方法研究

以冰模板法构筑的定向层状Al2O3气凝胶为模板，经浸渗并逐层吸附氧化铟锡（indium tin oxide，ITO）溶胶和Ag溶胶后，构筑具有定向层状孔结构特征的Al2O3-Ag/ITO气凝胶复合材料。通过阐明定向层状Al2O3气凝胶模板的构筑机理，明确模板的功能性改性方法及层间化学作用，实现气凝胶材料的微观结构精确控制。基于小角X射线散射和氮气吸附法等微观孔结构分析结论，利用单轴压缩和三点弯曲等力学性能分析手段，建立气凝胶力学行为与微孔结构之间的关系，阐明定向层状Al2O3气凝胶模板对力学行为的贡献机理，明确多孔材料强韧化的原因。通过材料的结构设计与分析，阐明引起材料传热各向异性的关键因素和机理，实现利用材料自身结构特征达到热管理的目标。本项目为气凝胶的微观结构控制与热管理调控方法等研究提供理论与数据支持，并为隔热材料的研究与应用奠定理论与实验基础。

The unidirectional lamellar alumina - silver embedded indium tin oxide （Al2O3-Ag/ITO） composite aerogels are constructed by layer-by-layer adsorption ITO sols and Ag sols into the unidirectional lamellar alumina aerogel templates synthesized by ice-templating methods. It is significant to investigate the construction mechanisms of alumina templates and the chemical actions between alumina templates and Ag/ITO sols in order to accurately control the microstructures of Al2O3-Ag/ITO composite aerogels and realize their functionalization. Porous structures of Al2O3-Ag/ITO composite aerogels are analyzed by the means of small-angle X-ray scattering and nitrogen adsorption method. Their mechanical behaviors are researched by uniaxial compression and 3-point beam benting. The relationships between mechanical properties and structural characteristics are built. The contribution for mechanical behaviors of unidirectional lamellar alumina aerogel templates is analyzed and the strengthening-toughening mechanisms of porous materials are explained. The target of thermal management based on own structural characteristics of the composites is realized by the structural design and analysis, in which the critical factors and mechanism of the anisotropic thermal condution are considered. Based on all these researches, the theory and experimental data will be obtained, which is benefited for understanding the microstructure control and thermal management regulative methods of aerogel composites, especially for the research of thermal insulations fields.