Titania Condensation by a Bio-Inspired Synthetic Block Copolymer

Abstract

Silicatein α, an enzyme found at the center of silica spicules in marine sponges, is known to play a role in silica condensation from seawater. It has also been shown to catalyze the formation of silica from various silica precursors such as tetraethyl orthosilicate (TEOS). Inspired by the finding that the serine-26 and histidine-165 amino acids in the enzyme are required for silica formation from TEOS, we synthesized poly(hydroxylated isoprene-b-2-vinylpyridine) block copolymers to mimic these amino acid residues. Here, we present the results of our investigation utilizing this biomimetic polymer to condense titania from titanium iso-propoxide (TiP). Our silicatein α mimic is shown to condense titania at neutral pH and room temperature and is compared to material produced by standard sol–gel methods. Heats of crystallization are observed to be 72% lower for the titania made from the mimic polymer, and indistinct X-ray diffraction peaks, even after heating well above the crystallization temperature, sugge...