Metal containing Electrically Conductive Polymers

Lin and Chiu [55] studied the effects of silver or copper particle composition (silver coated or uncoated copper), on particle shape (flake or spherical), particle size and oxidation temperature on the electrical properties of copper-filled epoxy resin electrically conductive adhesives. They also studied pressure dependent conduction behaviour of compressed copper particles. The silver-coated copper particles showed significantly greater oxidation resistance than un-coated copper particles because the 

Pourabas and Peyghambardoost [53] showed that copper filled epoxy resin composite had electrical conductivity properties. Afzal and co-workers [104] studied the electrical properties of PANI/silver nanocomposites. The silver nanoparticles in PANI reduced the charge trapping centres and increased the conducting channels of the polymer. 

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Table IV contains some comparative data regarding the electrical conductivity of some polychelates based on Fe3+ and Mn2+. The data dealing with electrical conductivity of polychelates, the starting polymers (for polyethylene terephthalate,

In the temperature interval of —70 to 0°C and in the low-frequency range, an unexpected dielectric relaxation process for polymers is detected. This process is observed clearly in the sample PPX with metal Cu nanoparticles. In sample PPX + Zn only traces of this process can be observed, and in the PPX + PbS as well as in pure PPX matrix the process completely vanishes. The amplitude of this process essentially decreases, when the frequency increases, and the maximum of dielectric losses have almost no temperature dependence [104]. This is a typical dielectric response for percolation behavior [105]. This process may relate to electron transfer between the metal nanoparticles through the polymer matrix. Data on electrical conductivity of metal containing PPX films (see above) show that at metal concentrations higher than 5 vol.% there is an essential probability for electron transfer from one particle to another and thus such particles become involved in the percolation process. The minor appearance of this peak in PPX + Zn can be explained by oxidation of Zn nanoparticles. 

By the process described above, a plasma film could be obtained that had high enough electrical conductivity to allow direct electrodeposition of copper. The bulk resistivity of film measured by a four-point probe was 2.6 x 10 " ohm-cm for the copper-containing polymer film when deposition was stopped after 18 min at HOW. This value is critical if a uniform electrolytic deposit is to be obtained. For safety, deposition was carried out until a total film thickness of 150nm was obtained, giving a nearly pure metallic layer thick enough to allow subsequent electroplating. 

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