One-step synthesis of hydrophobic silica aerogel via in situ surface modification

Using tetraethoxysilane (TEOS) and trimethylchlorosilane (TMCS) as co-precursors, we explore the one-step synthesis of hydrophobic silica aerogel via in situ surface modification at ambient pressure. Compared with hydrophilic feature of the products prepared by TEOS single precursor (without TMCS surface modification procedure), hydrophobic behavior of the aerogel obtained from TEOS and TMCS co-precursors was observed. Fourier Transform Infrared spectra (FTIR), Thermogravimetric analysis (TGA) and Si-29 NMR spectra were conducted to confirm the successful introduction of the hydrophobic group on the silica surface. In contrast to the multiple chemical modification approach, the procedure for one-step synthesis was simplified and the processing time was shortened from 2 weeks to 2 days. (C) 2012 Elsevier B.V. All rights reserved.