Conducting polymers adhesion promoters

FUms on these materials can be formed if adhesion promoters are used. With adhesion promoters it is possible to deposit films of conducting polymers on insulators, semiconductors with highly polished surfaces, and corrosive metals. An adhesion promoter consists of an adhesion group, e.g., chloro- or hydroxy silane groups, phosphonic acid groups, which can bond to the surface of the soUd, spacer group, and a monomer molecule as a head group. 

Electrically conducting polymers provide a new way to prepare conducting composites. It was shown in Chapter 11 how to prepare films of conducting polymers on non-conducting materials using adhesion promoters. The surface of the polymer became conducting. With the... 

In contrast, the PEDT PSS-complex is a prefabricated polymer, so film properties are instead adjusted by formulation — the addition of fibn-forming binders, surfactants, wetting agents, adhesion promoters, etc. The conductivity of unformulated PEDTPSS layers is rather low. However, conductivity can usually be increased during formulation by as much as 1 to 2 orders of magnitude. This is clearly in contrast to what one might expect— that the addition of nonconductive components would lower the overall conductivity ... 

Controlling the Morphology of Electronically Conductive Polymers. Convex Kel-F-insulated Pt disk electrodes (A 0.5 cm ) were constructed as described previously (32). The convex electrode surface promoted adhesion between the microporous membrane and the electrode surface (32). These electrodes were pretreated as described previously (32). Nuclepore polycarbonate microporous filtration membranes were used as the template material (32). Membranes with pore diameters of 0.02, 1.0 and 3.0 /im were used. 

Adding Teflon emulsion, conductive polymers, carbon liber, and rutile structured oxidate to PAM as adhesives can promote the transformation of a-Pb02 into p-Pb02, enhancing electrode performance. 

Recently, several conducting polymers have been explored as new electrode materials for neural interface. Polypyrrole, polythiophene, and their derivatives can be electrochemically polymerized from aqueous solution and deposited on the neural electrodes [22-28]. Bioactive molecules, such as cell-adhesion peptides, ECM proteins, growth factors, etc., can be incorporated into the polymer as dopants to promote neuronal growth and binding to the electrodes [22-25, 29-30]. Poly(3,4-ethylenedioxythiophene) (PEDOT) presents properties especially promising for... 

Conducting polymers can be prepared by chemical or electrochemical techniques. Electrochemical synthesis provides easier routes when compared with chemical synthesis and allows control over film formation, especially relevant if polymers are required as thin films deposited on the surface of metallic substrates. However, electrochemically synthesized polymers are usually more porous, a feature that requires consideration when a barrier effect is necessary. Another important aspect in the corrosion field is that the application of potential/current necessary to promote electropolymerization may accelerate dissolution (corrosion) of the metal. In some cases, an oxide pre-layer is deposited between the metal and the polymer to promote adhesion and hinder metal dissolution during the electropolymerization process (Tallman et al., 2002 Spinks et al., 2002). Alternatively, the application of layered coatings based on different conducting polymers can be a strategy to overcome the problem of metal dissolution. In the work of Lacroix et al. (2000), a layer of PPy was firstly deposited on zinc and mild steel in neutral conditions, followed by deposition of PANi in an acidic medium, because the direct deposition of PANi on those metallic substrates was not possible in an acidic medium, causing dissolution of the metal. 

Fig. 23-2 Procedure for the formation and transfer of electrically conductive polymer patterns onto insulating substrates. Step A application and development of patterned photoresist on the gold over mica substrate. Step B electrodeposition of electrically conductive polymer onto the exposed gold surface. Step C application of the adhesion promoter. Step D application of the insulator onto the adhesion promoting layer. Step E removal of the mica by immersion in dilute hydrofluoric acid solution. Step F etch removal of the gold layer by immersion in aqueous KI/I2 solution. Step G dissolution of residual photoresist in acetone. After Reference [955], reproduced with permission.

The introduction of nitrile groups into proton conductive sulfonated thermoplastics decreases their moisture absorption. Nitriles promote the adhesion of the polymers to heteropolyacids (HPA)s in composite membranes or to electrodes. In addition, the dimensional stability of the membrane is... 

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