Oriented Mesoporous Organosilica Films on Electrode: A New Class of Nanomaterials for Sensing

Abstract

We have recently reported the possible fabrication of highly ordered mesoporous silica thin films with mesopore channels oriented perpendicularly to the underlying substrate, by means of novel electroassisted self-assembly (EASA) method (Nature Mater. 6, 602 (2007)). Such films deposited on an electrode surface can be of great interest in sensing applications if one could introduce organo-functional groups likely to interact with target analytes in a regular environment ensuring great accessibility and fast mass transfer rates. We demonstrate here that aminopropyl-functionalized mesoporous silica films can be electrogenerated in one step by the sol-gel co-condensation route using cetyltrimethylammonium bromide as template. The orientation of the pore is maintained up to 10% aminopropyltriethoxysilane precursor in the starting sol. The presence of amine functions into the film affects its permeability to external reagents, as studied using various redox probes (Ru(bpy)3(2+), FcEtOH, I(-), Fe(CN)6(3-)), and the lack of mesostructuration was found to hinder dramatically mass transport processes. When applied to the voltammetric detection of copper(II) subsequent to open-circuit accumulation, the response of the electrode was greatly affected by the functionalization level, the optimal sensor sensitivity being defined from the best compromise between an amount of amine groups high enough while maintaining mesostructural order.

Electroanalytical Applications of Microporous Zeolites and Mesoporous (Organo)Silicas: Recent Trends

“…This advantage also belongs to electrodes modified with mesoporous silicas grafted with mercaptopropyl groups for which an increase of sensitivity by a factor 50 has been reported over an electrode containing similarly grafted silica gels of the same average porosity [145]. This is also true for film-based electrodes, as illustrated, e.g., for aminopropyl-functionalized mesoporous silica films electrogenerated with a mesopore orientation normal to the electrode surface, for which dramatically higher sensitivities were obtained in comparison to nontemplated films [238]. Of related interest are film electrodes prepared from functionalized porous clay heterostructures (PCHs), which result from the mesostructuration of the interlayer region of a clay with (organo)silica channels of monodisperse size (see, e.g., Fig.…”

Cyclam‐Functionalized Silica‐Modified Electrodes for Selective Determination of Cu(II)

“…Except few examples dealing with silica-based thin film electrodes [10,16,17], most of the works were based on CPEs modified with these adsorbents. The functionalized materials used for that purpose were prepared either by postsynthesis grafting of silica samples or in one step by the sol-gel process.…”

Electrode Materials (Bulk Materials and Modification)

“…621 Examples of electroanalysis using electrodes modified by mesoporous hybrid films have been reported for the detection of various metal species, such as Ag(I), 622 Hg(II), 623 Pb (II) 624 or Cu(II). 599 The typical experiment involves the preconcentration of the analyte in the mesostructured hybrid material, before its desorption/reduction in an appropriate detection medium, and subsequent electroanalysis, most often by stripping voltammetry. The selectivity of the adsorption allows in principle to preconcentrate preferentially the target metal from a complex solution containing potentially-interfering species.…”