Electrografting and electropolymerization of nanoarrays of PANI filaments through silica mesochannels

International audience; Vertically aligned mesoporous silica films electrogenerated on indium-tin oxide (ITO) electrodes are used as hardtemplates for the electrochemical growth of polyaniline (PANI) nanofilaments. To ensure proper adhesion ofPANI to the underlying ITO surface, aniline moieties are first covalently attached to the bottom of mesochannelsvia electrografting of aminophenyl diazonium cations, serving in a second step as precursors for PANI growth byelectropolymerization of aniline through the silica mesochannels. This was achieved by cyclic voltammetry orpotentiostatically at an applied potential of +0.85 V (vs. Ag/AgCl), the latter offering a better control of thenanofilaments length by tuning the electropolymerization time. PANI wires remain attached to ITO after etchingof the silica membrane, confirming the importance of initial electrografting. Although PANI nanofilaments in thesilica membrane remain electroactive, enhanced peak currents were observed after silica removal as PANInanofilaments offer a larger effective surface area to the electrolyte solution.