Direct metallization Conductive polymer systems

Although the anisotropy of conductivity in metallic oriented-]CH) or PPV-H2SO4 samples is nearly 100, the behaviour of the MC is identical whether the current is parallel or perpendicular to the chain axis. This suggests that high quality oriented conducting polymers behave as anisotropic three-dimensional systems in which the charge transport mechanism is nearly identical in both parallel and perpendicular directions to the chain axis. 

A conducting polymer, such as polyaniline, decorated with metallic or semiconducting nanoparticles furnishes an exciting system to investigate the prospect of designing device functionality directly into the material. A facile bulk synthesis method capable of producing high-quality polyaniline nanofibers, with... 

One investigative study that has raised considerable queries is the report of direct electrical communication between the active site of the enzyme and the conducting polymer when the enzyme is immobilized in polypyrrole microtubules. These microtubules were produced by electropolymerization of the pyrrole monomer inside the pores of a microporous filtration membrane. This configuration is reported to favor direct electron transfer across the polymer structure as well as direct reoxidation of the enzyme at lower potentials than typically used, hence promoting increased selectivity of the resulting amperometric biosensor [178]. Another report investigating the same system claims that it is the underlying platinum metal rather than polypyrrole tubules that is responsible for the observed direct enzyme reoxidation [179]. 

Conducting polymers have been used to modify the surface properties of metallic electrodes, in particular microelectrodes [49]. TTie prosthetic functional groups covalently attached to the polymer chains can be used as molecular sensors or molecular transducers that can reversibly transfer electrochemical information between the medium and the electrodes. These systems are useful for solution sensing in both amperometric and resistometric modes. Enzymes (for example, glucose oxidase) can be incorporated directly into the polymeric layer during polymerization and subsequently used as biosensors. 

Solid-state electrodes include devices in which the inner solution has been completely eliminated. The solution can be replaced with an all-polymer membrane formed directly on a metal reference electrode (CWE) a system of plasticized PVC (BMSA) or a substance with ionic-electron conductivity, a conductive polymer (SC ISE). 

We have demonstrated a novel method to create either fi eestanding or surface-boxmd wires capable of establishing electrical contacts between isolated metal structures. The technique relies on spatially coupled electrodissolution and electrodeposition mediated by an electric field. Such bipolar conditions avoid the need to physically contact the metallic components in the system, which should prove to be a considerable advantage when dealing with far smaller components. In the case of wire formation on circuit boards, the metallic paths laid down serve as templates for an electroless deposition step, which yields robust and adherent electrical connections. In principle, the method is not limited to planar geometries. The application of electric field vectors in selected directions through an array of conductive structures in a porous medium may represent a powerfijl approach to the formation of three-dimensional circuitry. Furthermore the use of a conductive polymer allows the use of metal structures which do not electrodissolve in the medium. 

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