Synthesis of Mesoporous Silica Helical Fibers Using a Catanionic-Neutral Ternary Surfactant in a Highly Dilute Silica Solution:  Biomimetic Silicification

Mesoporous silica helical fibers in many different shapes have been synthesized in a highly dilute silicate solution at pH ∼2.0 by using CnTMAB-SDS-P123 (n = 14−18) ternary surfactant as a template. The mesoporous silica helical fibers possess a well-ordered hexagonal mesostructure, high surface area, and large pore volume. Thus, the microtome sections of the helical fibers demonstrate a concentric mesotructure or two hemiconcentric mesostructures. In addition to triblock copolymer, adding the proper amount of 1-butanol or pentanol can promote the yield of the helical fibers as well. The yield of the surfactant-templated helical fibers is also dependent on the water content, reaction temperature, and pH value of the solution. The mesoporous silica helical fiber can be used as a solid template to prepare mesoporous carbon helical fibers via impregnation of phenol-formaldehyde, pyrolysis, and silica removal.