Biomimetic Synthesis of Silica with Its Morphology Mediated by Chitosan

Spherical, tabular, unique carambola-like shaped silica particles (see figure) are produced by the mediation of chitosan, a natural polyelectrolyte with abundant hydroxyl and amino groups. The silica morphology depends on the incubation time of the chitosan solution with phosphate ions before silicification. A sheet of the carambola-like silica made in this way has a granular surface, which inspires an “assembly–aggregation–silicification” model.