Electrochemical deposition of sol-gel films

Electrochemical deposition of sol-gel films has been developed for preparing solgel films since it was first clearly proposed in 1999. It is an indirect electrochemical deposition process, where the sol-gel film formation is catalyzed by electrochemically generated OH^- or H⁺ ions on the electrodes. Thus, it has merits in selectively coating conductive patterns and on electrode materials with high catalytic effect towards H₂ evolution. The thickness and morphology of sol-gel films can be well manipulated by deposition parameters such as potential, time, concentration of the sol precursor, and surfactants. Specifically, highly ordered mesoporous silica could be electrodeposited from solutions with cetyltrimethylammonium bromide (CTAB). The electrochemically deposited sol-gel films can be functionalized with various organic groups, such as amino, mercapto, pyridine, azide, and long-chain alkyl groups. The films may also serve as platform for incorporating a variety of species, such as metal, conductive polymer, enzymes, and bacteria, yielding various applications in corrosion protection, electrochemical sensing, binding bio-active materials, solid-phase microextraction, optics, and electrocatalysis. In this chapter, we first briefly reviewed the mechanism of sol-gel deposition and different electrodeposition techniques and then introduced the mechanism, manipulation, and applications of the sol-gel electrochemical deposition technique, including the electrochemical deposition of sol-gel films as well as sol-gel based hybrid and composite films.