二氧化硅气凝胶的常压低温快速制备和表征

Fast Preparation of Inorganic Silica Aerogels Under Ambient Pressure and Low Temperature and Its Representation

二氧化硅气凝胶凭借其极高的孔隙率和低导热性能已成为近年的热门研究材料之一。文章在常压低温条件下以正硅酸四乙酯为硅源,异丙醇和正己烷溶液为溶剂,通过低表面能溶剂置换以及粒子表面改性的方法快速制备无机气凝胶材料,并采用FE-SEM、HR-TEM、FTIR-ATR光谱及X射线衍射分析等手段对所制备气凝胶材料的表观形貌、化学结构以及结晶性能进行表征。研究表明：制得的二氧化硅气凝胶表面连有疏水的Si—CH3基团、存在丰富的介孔结构,粒子和孔隙的尺寸较小,是一种孔隙率高、轻质、且热稳定性较高的微晶纳米材料,具有广泛的应用前景。

With properties such as extremely high porosity and low thermal conductivity aerogels have become one of important modern materials being studied.In this research,inorganic silica aerogels are fastly prepared in an ambient-pressure and low-temperature method employing mainly low surface energy solvent exchange and particle surface modification with tetraethyl orthosilicate as the silicon source and the isopropanol and hexane solution as the solvent.The resultant mesoporous aerogels are represented through FE-SEM,HR-TEM,FTIR-ATR spectroscopy and XRD analysis with respect to apparent appearance,chemical structure and crystallization property.The results indicate that silica aerogels exhibit a sponge structure with narrow particle and pore size distribution,and there is obvious Si—CH3 group on the surface of silica aerogel;it is a kind of microcrystalline nanomaterial with high porosity,light mass and high heat stability which leads to its great potential application in many fields in future.