Effect of aluminium and copper acetylacetonate on physico-chemical properties of tetraethoxysilane based silica aerogels

Silica aerogel granules have been synthesized by doping aluminium acetylacetonate (Al(acac)3) and Copper acetylacetonate (Cu(acac)2), in the sol of tetraethoxysilane followed by ambient pressure drying process. The well established silica network provides effective confinement for metal particles which resists the collapse of silica network during ambient pressure drying of wet gel. In this paper, the effect of Al(acac)3 and Cu(acac)2 on physico-chemical properties of the aerogels have been studied by varying the concentration of both from 0.0005 to 0.05 M. The chemical composition, hydrophobicity and elemental analysis of Al(acac)3 and Cu(acac)2 doped silica aerogels were studied by using X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, contact angle measurement, X-ray diffraction, atomic absorption spectroscopy. The morphological study was carried by using transmission electron microscopy and surface area and pore diameter was measured by BET analysis. The thermal stability of hydrophobic nature was analyzed by simultaneous thermogravimetry and differential scanning calorimetry. The Al(acac)3 added silica aerogels are found to be superhydrophobic, low dense, high surface area and optically transparent as compared with Cu(acac)2 doped silica aerogels.