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.

Oriented Morphogenesis of ZnO Nanostructures from Water‐Soluble Zinc Salts under Environmentally Mild Conditions and Their Optical Properties

“…However, compared with the higher pH values required in earlier reports, the hydrolysis/condensation of the Zn/amine complexes furnished with PAA could take place at neutral pH. This result indicates that PAA has a similar role as has been proposed for polyaminemediated silicification in diatoms; [17,23] that is, the polyamines can bring the mineral precursors, which are formed via Zn/amine complexation, in close proximity to each other to allow their interaction, thereby forming Zn À O À Zn linkages. This role of PAA was further verified by carrying out the following control experiments: First, the reaction was carried out without using PAA, in which an aqueous solution of zinc nitrate was heated at 60 8C.…”

“…[14][15][16] Instead, our efforts have been focused towards using simple, positively charged polypeptides and related polyamines, which resemble biosilicification agents in diatoms, to synthesize and assemble nanomaterials under environmentally benign conditions. [17,18] Although this approach has led us to fabricate ZnO spindles and rods in a wet-chemical method, the process requires prior formation of Zn(OH) 2 and a longer reaction time (15 h). [18] Herein, we report our bottom-up approach utilizing water-soluble zinc salts for the mineralization of ZnO nanostructures in a very simple and versatile process.…”

Silicic acid condensation under the influence of water-soluble polymers: from biology to new materials

“…In this case, we must take into account that phosphate, citrate and other multivalent anions inuence the silicic acid condensation in the presence of polymeric amines resulting in precipitation of composites. 65,71 The ability of citrate ion to give aggregates with poly(allylamine) was utilized 77 to synthesize monodisperse 40-100 nm composite particles.…”

“…24,61,62,[65][66][67][68][69][70][71][75][76][77]98,99,[106][107][108]111,112,114,117,121,124,134,135,137,139,143,149,153,155,157 These variants exist in the case of relatively low silicon content in the system, when all PSA nanoparticles can nd chains of organic polymer. Further increase in the silicic acid content results in formation of insoluble non-uniform products 64,83 because of cross-linking by means of silicic acid which was condensed independent of the polymer control.…”

Core-Shell MnO2-SiO2 Nanorods for Catalyzing the Removal of Dyes from Water

“…The positively charged amine groups on the surface of MnO 2 @PDA-PEI provide prerequisites for further silicification [31]. When MnO 2 @PDA-PEI was added to the solution of TEOS, electrostatic interactions occurred between the positively charged amine groups of PEI and negatively charged silicic acid resulted from the hydrolysis of the methyl groups of TEOS [31]. Protonated and nonprotonated amine groups of the PEI chains formed hydrogen bonds with the oxygen, facilitating the formation of Si-O-Si bonds.…”