Conducting polymers with metal

These results clearly confirm that modifying a conducting polymer with metallic particles containing Pt, Ru, and Mo leads to enhanced catalytic performances versus the oxidation of methanol in comparison to the behavior of binary catalysts (Pt-Ru). 

Another mechanism of the interaction of conducting polymers with metal surfaces is based on the idea that the conducting polymer passivates the metal that is to be protected [56]. The polymer is reduced to the neutral form. As a compensating... 

Nanocomposites of conducting polymers exhibit improved physicochemical and biological properties as compared to their individual counterparts. The integration of secondary component within conducting polymer leads to dramatic increase in different properties that are useful from an application point of view. Size, shape and controlled distribution of the dispersed phase are the critical factors to control the desired properties of a nanocomposite. Different approaches such as in situ synthesis, one-pot synthesis, electrochemical polymerization and vapor-phase polymerization have been employed to synthesize the nanocomposites of conducting polymers with metal or metal oxide nanoparticles, carbon-based materials, ternary nanocomposites, etc. All of these methods have certain advantages and drawbacks. Functional nanocomposites synthesized by these methods display many... 

Because polymers have a very low thermal conductivity, compared with metals, cooling from the melt proceeds unevenly, the surface cooling more... 

These results illustrate that electrochemical techniques can be employed to synthesize a vast range of [Si(Pc)0]n-based molecular metals/conductive polymers with wide tunability in optical, magnetic, and electrical properties. Moreover, the structurally well-defined and well-ordered character of the polymer crystal structure offers the opportunity to explore structure/electro-chemical/collective properties and relationships to a depth not possible for most other conductive polymer systems. On a practical note, the present study helps to define those parameters crucial to the fabrication, from cheap, robust phthalocyanines, of efficient energy storage devices. 

The interaction of poly(ethylene oxide) and other polar polymers with metal salts has been known for many years (Bailey and Koleska, 1976). Fenton, Parker and Wright (1973) reported that alkali metal salts form crystalline complexes with poly(ethylene oxide) and a few years later, Wright (1975) reported that these materials exhibit significant ionic conductivity. Armand, Chabagno and Duclot (1978, 1979) recognised the potential of these materials in electro-chemical devices and this prompted them to perform more detailed electrical characterisation. These reports kindled research on the fundamentals of ion transport in polymers and detailed studies of the applications of polymer-salt complexes in a wide variety of devices. 

Chitosan is a polymer with metal-binding properties that is derived from naturally occurring chitin. Research has been conducted on the potential use of chitosan in hazardous waste remediation. While chitosan does bind transition metals, it favors iron, a nonhazardous metal, which competes and interferes with chitosan s binding of toxic metals. Copper also tends to be highly bound, while the amount of cadmium and lead removed is lower. The technology is still undergoing testing and is not yet commercially available. 

It is also possible to reinforce polymers with metallic particles. D. T. Turner and one of his students observed that good electrical conductivity can be measured even at very low fillings, such as only 6% by volume. Microscopic examinations showed that the metallic particles formed continuous chains segregated around zones of unpenetrated polymer. 

Some conducting polymers with a conjugated polyvinyl structure, such as polyacetylene and poly(phenylacetylene), seem likely to be energetic enough, and reactive enough, to give trouble undoped, if they actually have the supposed structure [7]. See Ethylene, Butadiene, Styrene See related NON-METAL PERCHLORATES... 

Turner, B. E. 1971 Detection of interstellar cyanoacetylene. Astrophys. J. 163, L35-L39. Wegner, G. 1981 Polymers with metal-like conductivity. A review of their synthesis, structure and properties. Angew, Chem. Int. Edn. Engl. 20, 361-381. 

An even better effect is created by blending the polymer with metal fibres, e.g. for shielding electric fields. Even a small amount of these fibres is able to form a network, which considerably increases the conductivity. 

In oriented metallic conducting polymers, with large anisotropy in conductivity, the anisotropic diffusion coefficient factor should be taken into account in the above model. The robustness of this metallic state can be verified from the field dependence of conductivity at low temperatures. For example, in the case of sample E with oj 2 200 S/cm (see Fig. 3.4), which is just on the metallic side of the M-I transition, a field of 8 T can induce a transition to the insulating state, as shown in Fig. 3.7. The corresponding W vs. T plot (Fig. 3.7a) is consistent with the fact that the system has moved from the metallic to the critical/insulating side. This is a typical example... 

In general, polymers are insulating materials having conductivities ranging from 10 ° (fl cm)" for poly(vinyl chloride) to 10" (ft cm) for poly(tetrafluoroethylene), which are many orders of magnitude below the conductivities associated with metals (Figure 1.13). Indeed, low conductivity (and consequent low dielectric constant) is one of the major reasons polymers have found widespread acceptance in a myriad of insulating and structural... 

Ohmura, K. Kijima, M. Shirakawa, H. Synthesis of conducting polymers with conjugated carbon-carbon triple bonds by electrochemical condensation of acetylene derivatives catalyzed by copper complex. Synth. Metals 1997, 84, 417-418. 

The poor heat transfer characteristics of polymers has been seen in Figure 4 Combining polymers with metals gives only marginal improvements. Only direct-access through-holes in the insulator can produce improved assemblies. Even then, the conductivity is less than that of the base metal because some attachment material will be used. 

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