Synthesis of radial silicas: A dynamic templating approach

Abstract Understanding how radial growth of silica spines on synthetic silica spheres relates to the biosilification mechanism on their analogous biological diatoms will help to better understand the natural process. However, the number of reports of the growth of silicas with radial spines is few. In this work we report the synthesis and use of a pair of low-molecular-weight amphiphiles derived from 1,2-diphenylethylenediamine to form chiral aggregates in deionized water at a concentration of 25 g L−1 at 25 °C. Silica nanotubes and hollow nanospheres with radial spines are prepared using one of the amphiphiles as the template, 3-(aminopropyl)trimethoxysilane as a co-structure-directing agent and tetraethyl orthosilicate as the silica precursor. The pH value of the reaction mixture plays an important role in the formation of radial spines, which are found to grow within the pH range of 7.43–10.52. It is proposed that the hierarchical nanostructures form through a dynamic templating process.