Electrochemically assisted self-assembly of ordered and functionalized mesoporous silica films: impact of the electrode geometry and size on film formation and properties

• DOI: 10.1039/c3fd00021d
• Publication Date: 2013-04-24T10:30:32Z
• Authors: Grégoire Herzog; Emilie Sibottier; Mathieu Etienne; Alain Walcarius
• Keywords: Ammonium bromide; Deposition; Silsesquioxane

Surfactant-templated mesoporous silica thin films can be deposited onto solid electrode surfaces by electrochemically assisted self-assembly (EASA). The method involves a cathodically triggered of cationic surfactants (cetyltrimethyl ammonium bromide, CTAB) and local pH increase leading to the polycondensation precursors (i.e., tetraethoxysilane, alone or in presence (3-mercaptopropyl)trimethoxysilane (MPTMS)) concomitant growth ordered organosilica film. present work shows that EASA applied film deposition on supports various morphologies, geometries sizes (large flat discs non-flat streaked supports, i.e., gold CD-trodes, as well several kinds ultramicroelectrodes, including carbon fibers, platinum wires, microdiscs). Galvanostatic conditions were mainly preferred potentiostatic avoid problems related overpotentials surface areas experienced with working electrodes used here. results indicate was possible each support but also both formation properties dependent experimental for EASA. For example, passing from large ultramicroelectrodes required application larger current densities ensure deposition, which due faster loss hydroxyl species solution case radial spherical diffusion, comparison linear. Highly porous deposits obtained after template removal, ascertained cyclic voltammetry using Ru(NH3)63+ redox probe. advantage better signal-to-background ratios relative macroscopic ones maintained resulting higher sensitivity when preconcentration electroanalysis (using silver(I) mercury(II) probe being accumulated complexation MPTMS-based films).