Coating methods solution-phase

Chemisorption requires direct contact between the chemisorbed molecule and the electrode surface as a result, the highest coverage achievable is usually a monomolecular layer. This may be contrasted with several of the methods to be discussed later that allow the electrode surface to be covered with thick films (i.e., multimolecular layers) of the desired molecule. In addition to this coverage limitation, chemisorption is rarely completely irreversible. In most cases, the chemisorbed molecules slowly leach into the contacting solution phase during electrochemical or other investigations of the chemisorbed layer. For these reasons, electrode modification via chemisorption was quickly supplanted by other methods, most notably polymer-coating methods. 

One method to render silica aerogels conductive is to conformally coat them with a secondary conductive phase. This was demonstrated by Rolison and co-workers by solution-phase treatment of silica aerogels with RUO4 at low temperatures, which subsequently decomposes to plate RUO2 on the aerogel surface (19). 

Beyond PVD and CVD, there are techniques from the liquid/solution phase such as sol-gel, spray coating, spin coating, electrochemical deposition and liquid phase epitaxy. The sol-gel process is the most widely used method for the deposition of metal oxide for gas sensors. 

The immiscible chemical phases are (1) a liquid manufacturing vehicle phase, (2) a core material phase, and (3) a coating material phase. To form the three phases, the core material is dispersed in a solution of the coating polymer, the solvent for the polymer being the liquid manufacturing vehicle phase. The coating material phase, an immiscible polymer in a hquid state, is formed by utilizing one of the methods of phase separation coacervation, that is,... 

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