Conductive Polymers electrical contact performance

ELECTRIC CONTACT PERFORMANCES AND ELECTRICAL CONDUCTION MECHANISMS OF AN ELASTOMERIC CONDUCTIVE POLYMER... 

Electrically conductive adhesives owe their conductivity as well as their high cost to the incorporation of high loadings of metal powders or other special fillers of the types shown in Table 9.8. If enough metal particles are added to form a network within the polymer matrix, electrons can flow across the particle contact points, making the mixture electrically conductive. Virtually all high-performance conductive products today are based on flake or powdered silver. Silver offers an advantage in conductivity stability that cannot... 

Bipolar plates are the components performing a number of tasks such as reactant supply, heat exchange, electron transfer to the external circuit, physical strengthening of the cell, etc. The material requirements for bipolar plates include high mechanical strength, corrosion resistance, electronic conductivity, low density, etc. [154]. CNT/polymer compos-ites-based bipolar plates enhance the fuel cell performance considerably [155,156]. The relevant properties such as electrical conductivity, mechanical strength, contact resistance and chemical inertness of the composites exhibit large improvements in PEM fuel cells [157-159]. 

For conductive AFM measurements, the tip was kept in contact with the sample surface while the current through the tip was measured. In contrast to operating in intermittent contact (IC) mode, contact mode is characterized by a strong tip-sample interaction that can lead to destruction of the surface, especially in the case of soft polymer samples. Therefore, the load applied to the tip during C-AFM has to be small enough to reduce sample destruction and, at the same time, it must provide a reliable electric contact. We usually operated with a load of about 10-20 nN. The contact cantilevers used for C-AFM are suitable for operation in IC as well as in contact mode so that nondestructive testing of the sample surface could be performed before and after the C-AFM measurements. C-AFM measurements of the... 

NiO is a semiconductor and after first Li insertion, the pristine particles are disintegrated and resulting in poor electrical contact, which gives rise to poor cycling performance. One effective way to solve this problem is to compose the pristine NiO with a conductive material, like carbon, metal and conductive polymer. 

The conductive polymer is usually composed of dispersed electrically conductive particles such as carbon black or metal in a durable polymer matrix such as silicone rubber. As it is possible to obtain conductivity and elasticity in simple materials, this is useful for high density micro-sized electrical contacts as connector or as key-board switch. However, in spite of the excellent properties, it is difficult to obtain low electrical resistivity. In order to approach this problem, performances of the contacts between the polymer surface and metal were studied from the view point of surface contamination. The electrical conduction mechanism and a method to get low resistivity were also studied. The results show that the surface of the polymers containing carbon black shows contamination resistance properties because of their chemical stability. The conduction mechanism changes with particle content. For large content, electric current flows through particles contacting each other and for small content, the current passes through the gap between particles by Schottky conduction. Thus, as the resistance consists of particle resistance, constriction resistance and gap resistance, the resistance can be controlled by particle material, their content and size. 

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