Patra, Amitava and Ganguli, Dibyendu (1992) Effects of Zn2+ doping on the sol-gel transition and optical properties of gels in alkoxide-derived silica. Transactions of the Indian Ceramic Society, 51 (5). pp. 105-109. ISSN 0371-750X

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Doped silica sols were prepared via hydrolysis and poly-condensation reactions involving Si(OC2H5)4 and water in which 0.5–10 mol% equivalent of ZnO was added through Zn(NO3)2.6H2O. Gelation was found to be progressively accelerated with increasing amount of Zn2+ which was suggested to link the silicate polymeric clusters via terminal SiO− groups. Activation energies of the overall process of gelation (calculated from gelling times at 10°, 30°, 40° and 50°C) showed significant drop with increasing dopant content. Optical absorption edges of the gels obtained after heating at 500° and 700°C showed progressive shifts towards longer wavelengths with Increasing Zn2+; the optical band gap recorded a corresponding decrease, suggesting this to be an effect of formation of non-bridging Si-O-Zn groups. Another kind of non-bridging group, namely Si-OH, was found by Infrared spectroscopy to decrease in amount with increase In the temperature of heating.

Item Type: Article
Subjects: Engineering Materials
Depositing User: Bidhan Chaudhuri
Date Deposited: 02 Dec 2013 13:09
Last Modified: 05 Mar 2016 14:29

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