Tuned conductive coatings

Tuned Conductive Coatings. One of the major uses of conductive polymer coatings is in electrostatic discharge protection. For effective electrostatic discharge protection, the ideal situation is one wherein the electrical charges are dissipated nearly as rapidly as they are generated. In order to do this effectively, the surface resistance of the packaging material should be less than 10 ... 

V. G. Kulkarni, Tuned conductive coatings from poly-aniline, Synth. Met. 77 2129-2131 (1995). 

Thin films are layers of material ranging in thickness from nanometers (10" m) to micrometers (10" m). They are used commonly for coating optical surfaces and also for coatings on semiconductors. Thin films are used to make mirrors, and these can be finely tuned (in terms of their composition and thickness) to obtain optical surfaces with a wide variety of specific reflection properties, such as wavelength specific mirrors and two-way mirrors (the ones that are transparent from one side but reflective from the other). Thin films are also very useful for coating semiconductors to tune their conductive properties for different applications. 

Sapurina et al. have reported the synthesis of PANI-coated waterborne polyurethane latexes in the presence of a polymeric stabihzer, polyvinylpyrrolidone (PVP). The composite particles showed a conductivity of 10 S cm i, with good colloidal and mechanical properties [73]. Recently, Huang et al. synthesized a series of PPy-coated styrene-butyl acrylate (SBA) core-shell latex particles [74], The Tg of the composite particles was shown to be determined mainly by the core material. It was reported that the conductivity of the hybrid particles could be tuned by varying the butyl acrylate content in the SBA copolymer. The composite particles showed a conductivity of 0.17 S cm Composite particles having a photochromic dye as the core and ICP as shell, and possessing properties of photoluminescence, have been studied by Jang etal. [75]. Thin PEDOT-coated PS particles (Fig. 6.14) were reported for self-assembled crystalline coUoidal arrays with a stop band in the visible regime by Han and coworkers [76]. 

Conjugated polymers are very significant, smart, or responsive materials. Indeed, many properties (color, conductivity, volume, hydrophiHcity, permeability, etc.) depend on their oxidation state and can thus be reversibly controlled by the potential applied to the material. As an example, smart windows [2] are based on the electrochromism of these coatings, that is, the ability to switch these polymers reversibly between dark and colorless state by simple control of the polymer redox state. The intensity of Hght transmission through a window incorporating such a layer can thus be tuned at will by external electrical stimuli. 

Electrodeposition is a well-known method to produce in situ metalhc coatings by the action of an electric current on a conductive material immersed in a solution containing a salt of the metal to be deposited. Moreover, by controlhng synthesis conditions, the electrochemical synthesis/deposition can be used to produce thin films of oxides and/or l droxides on conductive materials [12]. The composition, morphology and texture of the film coating can be controlled by tuning the experimental parameters such as the potential, current density, deposition time, and plating solution composition. In... 

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