THE IMPACT OF ALKYL CHAIN LENGTH ON THE PROPERTIES OF SiO-BASED AEROGELS

Modified silica aerogels were obtained by co-gelation of tetramethoxysilane and acylated 3-aminopropyl-trimethoxysilane (with the general formula (MeO)-Si-(CH)-NHCO-R), followed by supercritical drying in CO. Methyl esters of acetic, valeric, pelargonic, and stearic acids were used as acylating agents. The resulting aerogels were characterized using low-temperature nitrogen adsorption, scanning electron microscopy (SEM), and infrared spectroscopy (IR). It was shown that the specific surface area of the aerogels significantly depends on the length of the alkyl substituent in the modified silane and can vary from 40 to 1375 m/g. An increase in the length of the alkyl substituent also leads to increased hydrophobicity of the aerogel, up to the formation of superhydrophobic materials (contact angle is 163.7°).