Study the Effect of Doping with Chromium Chloride on Silica Aerogel Properties Prepared with Ambient Pressure

Abstract

Hydrophobic silica aerogel have been prepared through two step acid-base catalysis recipe, via ambient pressure drying method. tetraethylorthosilicate was used as precursor, and trimethylchlorosilan as surface modifier. Three adopted molar concentrations of Chromium chloride are used; 0.019, 0.032, 0.051 [M]. In this paper, the molar ratio of chemicals; precursor, alcohol and catalyst, was kept constant at (1:8.6:0.23) respectively. The hydrophobic property was obtained by socking the final gel in trimethylchlorosilan -hexane solution at 6 wt. % of modifiers in hexane. The physical properties of the prepared aerogel samples; optical, structural and morphological were examined through UV-VIS spectroscopy, FTIR spectra, X ray diffraction, contact angle measurement and field emission scanning electron microscopy. The results indicate that, the doping process offers an enhancement of the aerogel hydrophobic property. As well as, the doped aerogel being of lower density, relatively have smaller particle size and of more homogenous surface.