Bioinspired Silicification of Functional Materials: Fluorescent Monodisperse Mesostructure Silica Nanospheres

Abstract

Herein we demonstrate a simple but versatile bioinspired polyamine-catalyzed silicification route to synthesizing functional materials which is monodisperse, mesoporous, and spherically uniform having nanosizes under extremely mild conditions similar to the biosilicification processes. Employing the principles learned from nature and in particular from diatom biomineralization to integrate the functions required for silica condensation and self-assembly leads to the formation of such functional materials. Importantly, the integration of such functions requires the presence of suitable multivalent counteranions, whose interaction is structure specific while facilitating the mineralization process to form these unique silica structures under the green conditions of aqueous medium, neutral pH, and room temperature. The versatility of the method is exemplified in controlling the size, uniformity, and the nanoarchitectural features of the silica obtained within a very short time frame of 30 min. A wide variety of techniques (fluorescence imaging, live confocal imaging, dynamic light scattering, MAS 29Si NMR, N2 sorption, X-ray diffraction, FT-IR, thermo-gravimetric analysis, scanning and transmission electron microscopy) have been used to study the formation process and characterization of the materials.