块状气凝胶的结构和品质优化及其机制研究

By selecting various precursors, adding appropriate DCCAs (Drying Control Chemical Additives) in solutions, and adjusting the parameter of the sel-gel process, the alcogels with perfect network structure are obtained. Combined with the following measures such as immersing of gels in the ethanol solutions of organometallic alkoxide, exchanging the pore fluid by a certain solvent with low surface tension, and gradual aging and drying, the two crucial problems of the research and development of aerogels are resolved. Control on microstructure and optimization of qualities of aerogels are realized. The uniformity of nano-particles and network pores of the resultant aerogels are improved with a concomitant improvement in the properties such as the mechanical strength, monolith and transparency obviously. The aerogels' preparation technology including supercritical drying technique are simplified. Our newly-set up technique for preparation of aerogels via non-supercritical drying, which results in the improvement of the preparation condition, the shortening of their production period, and the drop of the costs of production, is creating optimum conditions for farther researches and practical applications of aerogels. Based on this technique, the extending research on aerogels have broken through, and will open up a new research field. According to the research program and target predetermined, this project has been well accomplished.

气凝胶是纳米量级胶体粒子聚集成的均匀固态低密度高分散体系，由于其结构和性质的特异性以及广阔的应用前景而受到多方面的重视。本项目通过在介观层次上引入各种受控源物质、对溶胶----凝胶过程条件的筛选控制、超临界干燥工艺的改进、以及对气凝胶的后处理等，达到对气凝胶的微细结构控制和剪裁，实现品质优化并阐明其优化机制。