Influence of Hydrolysis Time on Properties of SiO_2 Aerogels Prepared by Ambient Pressure Drying

摘要

With ethyl orthosilicate as precursor and trimethylchlorosilane as surface modifier, hydrophobic SiO_2 aerogels are preparedthrough sol–gel process combined with ambient pressure drying process. The influence law of different hydrolysis times onmicrostructure and physicochemical properties of aerogels when the reaction precursor is in the sol phase is studied. Theresults show that the hydrolysis time increases from 6 to 36 h, and the prepared aerogels have nanoscale mesoporous structureand hydrophobic properties.With the increase in hydrolysis time, the porosity and specific surface area of the samples increaseand then decrease, and the density decreases and then increases, all of which reach their peaks at 18 h. The properties ofsamples are optimal after being hydrolyzed for 18 h. The prosperity is 96%, specific area is 1539.7706 m~2/g, the density is0.08921 g/cm~3, and the contact angle is 148.3°.