常压干燥法制备气凝胶的研究进展

气凝胶是一类轻质、低密度的三维纳米多孔固态材料，因其独特的高孔隙率、高比表面积和低导热系数等特性，使其在吸附、催化、保温隔热和隔音等诸多领域具有广泛的用途，目前其相关研究在材料科学领域受到了广泛的关注。气凝胶的制备主要包括溶胶-凝胶过程和湿凝胶干燥两个步骤，湿凝胶的干燥是制备气凝胶过程中至关重要而又较为困难的一步。传统的气凝胶通过超临界干燥制备，工艺复杂、成本高，而且由于干燥过程在高温高压条件下进行，有一定的危险性并且不适宜大规模生产，因此如何通过常压干燥获得高比表面积、高孔隙率、低密度的性能优异的气凝胶是其研究的重要方向之一。本文简要介绍了湿凝胶的制备以及凝胶干燥理论，详细介绍了近年来常压干燥方法气凝胶制备的研究进展，并对其未来发展前景做出了展望。

Progress in Aerogels Preparation by Ambient Pressure Drying Processes

Aerogel is a light-weight, low-density three-dimensional nanoporous solid. Because of its high porosity, high specific area, low thermal conductivity etc., it has a wide range of applications in fields such as absorption, catalysis, thermal and acoustic insulation, and its related research has received extensive attention in the field of materials science. The preparation of aerogel mainly includes two steps: sol-gel process and wet gel drying. Gel drying is a crucial and difficult step in its preparation. Because the traditional aerogel preparation is realized by supercritical drying involving high temperature and high pressure, the drying processes are somewhat complicated, costly, dangerous and not suitable for mass production. Therefore, how to obtain aerogels with high specific surface area, high porosity, and low density and excellent performance through ambient pressure drying has become one of the important directions for the aerogel research in recent years. This review gives a brief introduction to the drying theory of wet gels and the preparation of aerogels, a detailed introduction to the progress in the ambient pressure drying methods of aerogels in recent years, and a prospect for its future development.