Corrosion Protection and Adhesion Promotion

The electrochemical deposition approach was initially used for depositing orga-nofunctional silane sol-gel films for promoting adhesion between aluminum alloy and epoxy resin [Ij. Later, it was used for preparing silane films for corrosion protection of metals, electrochemical stripping analysis of metal ions, and microextraction of organic compounds [18,20,22,42,45]. The recent development of the electrochemical deposition of sol-gel-based composite films opens various applications such as encapsulating proteins, enzymes, and bacteria. In this section, we will show three main applications of eiectrodeposited sol-gel films, that is, corrosion protection and adhesion promotion, electrochemical sensors, and finally biocomposite films. Other applications such as solid-phase microextraction (SPME), nonlinear optics, antireflection, electrocatalysis, and superhydrophobic films are also discussed. 

Several approaches have been reported by Hu and coworkers to further improve the anticorrosion performance of electrodeposited silane sol—gel films. They found that adding proper concentration of nitrate ions into the silane deposition solution facilitated the electrodeposition process by reducing nitrate to nitrite, and thus enhanced the corrosion resistance of the films obtained [31]. Co-electrodeposition of silane with silica or titania nanoparticles [47,49], or Ce (N03)s [77], ako improved the films anticorrosion performance. Small content of nanoparticles was foimd to increase the compactness of the electrodeposited silane films. Ce(III) provided a self-healing effect for long-term immersion of the dip-coated Ce(III)-doped bis(triethoxysilylpropyl) tetrasulfide (BTSPS) films in 

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