Silica Synthesis Using Polyanions and Other Systems

Silica Synthesis Using Polyanions and Other Systems 

Further, to demonstrate that negatively charged polymers will not catalyze silica formation under these conditions, in the way discussed above for PASA, and that there might be some specificity of the cationic charge in the polymers, we used PAAcid and PMA (Table 1). As expected, neither of the polymers facilitated the precipitation of silica and they each formed gel in 1 day. 

PPV precmsor (Table 1) precipitated sihca and did not gel, but the silica produced did not have a well-defined structure. However, the ability of PPV to precipitate silica and not gel can be used. The precipitate can be dried and can be powdered for suitable applications in photovoltaic devices. The precipitate, when left in a test tube, was seen to change its color from white to light blue in 3-5 days and then to bluish green in 5-7 days. The conversion of the PPV precursor to PPV within the inorganic-organic hybrid system and the optical properties of this hybrid are currently being investigated. 

A water-soluble Ceo-fiiUerene (Table 1) was studied for its ability to form sil-ica. The frmctionahzed Ceo-fuUerene did not precipitate silica, and neither did it gel in 24 h. Fullerene-sUica hybrid materials find applications in photovoltaic devices and related opto-electronic applications. 

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D. Silica Synthesis Using Polyanions and Other Systems 219... 

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