Silver Nitrate/Oligo(ethylene Oxide) Surfactant/Mesoporous Silica Nanocomposite Films and Monoliths

ISSN： 0021-9797

Source： Journal of Colloid and Interface Science, Vol.238, Iss.1, 2001-06, pp. : 203-207

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Abstract

A lyotropic, liquid crystalline (LC) phase of a silver nitrate/oligo(ethylene oxide), water, and acid mixture was used for one-pot synthesis of mesoporous silica materials in which Ag⁺ ions are uniformly distributed. We established that the AgNO₃-to-surfactant mole ratio is very important in a 50 wt% surfactant/water system to preserve the hexagonal LC phase before and after the addition of the silica source. Below a 0.6 AgNO₃-to-surfactant mole ratio, the mixture is liquid crystalline and serves as a template for silica polymerization. However, between 0.6 and 0.8 AgNO₃-to-surfactant mole ratios, one must control the composition of the mixture during the polymerization processes. Above a 0.8 mole ratio, Ag⁺ ions undergo phase separation from the reaction mixture by complexing with the surfactant molecules. The resulting silica materials obtained from AgNO₃/surfactant ratios above 0.8 have anisotropy but without a hexagonal mesophase. Here, we establish a AgNO₃ concentration range in which the LC phase is preserved to template the synthesis of mesoporous silica, and we discuss the structural behavior of the mixtures at AgNO₃/surfactant mole ratios of 0.00–2.00, using POM, PXRD, FTIR, and UV–Vis absorption spectroscopy.