Polysaccharides as a template for silicate generated by sol-gel processes.

The polysaccharides, as established previously (Yu.A. Shchipunov, J. Colloid Interface Sci. 268 (2003) 68; Yu.A. Shchipunov, T.Yu. Karpenko, Langmuir 20 (2004) 3882), can manipulate the formation of hybrid silica nanocomposites by sol-gel processes. Here atomic force microscopy was applied to show whether carbohydrate macromolecules serve as a template for silicate. Mica was used as a substrate to adsorb polysaccharide. It was found that its surface is not neutral to the sol-gel processes, providing the silica precipitation. To hinder it, the mica was protected by a monomolecular film of arachidic acid with the help of a Langmuir-Blodgett technique. Hydrophobically modified cationic hydrohyethylcellulose was adsorbed from a diluted aqueous solution. It was demonstrated that the carbohydrate macromolecules located on the hydrophobic surface did promote silica precipitation, serving as a template.