Non-peptide polymeric silicatein a mimic for neutral pH catalysis in the formation of silica

We have synthesized a catalytically active polymer inspired by the naturally occurring protein silicatein a and have shown it to catalyze the formation of silica from tetraethoxysilane under near-neutral pH and ambient temperatures. We based the composition of the polymer on the functionalities found in silicatein a, specifically those essential components of the catalytically active site for the hydrolysis of silicon alkoxides. Our bioinspired polymer is a block copolymer of poly(2-vinylpyridine-b-1,2- butadiene), functionalized by the addition of hydroxyl groups via hydroboration chemistry. The catalytic action of our polymer on tetraethoxysilane at neutral pH and ambient temperature conditions has been confirmed using a modified molybdic acid assay method, thermogravimetric analysis, and Fourier transform infrared spectroscopy. The structure of the resulting gel is investigated by scanning electron microscopy and solid-state nuclear magnetic resonance. The microscopic features of the material formed resemble that of gels formed by the acid-catalyzed hydrolysis of tetraethoxysilane.