Electrochemical characterization of insulating silica-modified electrodes: Transport properties and physicochemical features

•Electroinactive sol-gel silica multilayers were deposited onto ITO electrodes•Physicochemical and electrochemical (CV, EIS) measurements were performed•Electrochemical trends related to the number of silica layers deposited were observed•The electrochemical response was attributed to variation in the diffusion coefficient•An increase in hydrophilicity as the number of layers increased was correlated with diffusion enhancement

The effect of depositing different numbers of insulating layers from a silica sol onto an ITO support was investigated to elucidate the changes occurring to diffusion and transfer mechanisms compared with bare electrodes. The electrochemical studies highlighted unexpected trends, which were discussed with respect to literature models and interpreted in the light of the physicochemical characterization (by FE-SEM, AFM, UV-vis transmittance) and particularly the hydrophilicity of the layers.