Adsorption and electropolymerization of toluidine blue on the nano structured octakis(hydridodimethylsiloxy)-octasilsesquioxane surface

Abstract

Toluidine blue O (TBO) was adsorbed on the octakis(hydridodimethylsiloxy)octasilsesquioxane (Q(8)M(8)(H)) surface. The characterization of the precursor (Q(8)M(8)(H)) and resulting materials obtained by the reaction of Q(8)M(8)(H) and toluidine blue (CTBO) were defined using Fourier transform infrared spectra, nuclear magnetic resonance solid-state (13)C and Si(29) magic angle spinning. The electrochemical polymerization in a glassy carbon electrode was verified by means of a film silsesquioxane formation (FCTBO) using cyclic voltammetry in a potential range of -0.5 to 1.3 V (vs. saturated calomel electrode (SCE)) in a Britton Robinson (B-R) buffer solution (pH 2.0). The cyclic voltammogram of the film exhibits two redox couples with a formal potential of -0.15 and -0.02 V (B-R buffer pH 5). The formal potential shifts linearly in the cathodic direction by increasing the pH solution with a slope of 71 and 57 mV per unit for the first and second couple, respectively. The film was electrochemically very stable. (c) 2008 Elsevier Ltd. All rights reserved.