Electrical Conductivity Properties

The electrical properties of intelligent materials are important as they determine the following  

Electrical conductivity in PPy involves the movement of positively charged carriers and/or electrons along polymer chains and the hopping of these carriers between chains. It is generally believed that the intrachain hopping resistance is much greater than the interchain transport resistance. 

FIGURE 3.1 Highly conducting islands of polymer in a sea of amorphous, less conducting polymer. 

Electron and x-ray diffraction data suggest that the polymer chains in elec-trochemically synthesized PPy lie parallel to the substrate electrode surface, as described in Chapter 2. This is reflected in the anisotropic nature of the conductivity of PPy.1 The resistance along the surface of the film is known to be less than that across the film. However, this anisotropy is lost with thicker films. 

Conductivity within conducting electroactive polymers (CEPs) is a complex issue. A polymer that can exhibit conductivity across a range of some 15 orders of magnitude most likely utilizes different mechanisms under different conditions. In addition to the electronic conductivity exhibited by CEPs, they possess ionic conductivity because of the solvent or electrolyte incorporated during synthesis. The experimental parameters encountered during synthesis (as listed and discussed in Chapter 2) have an effect on the polymer conductivity. In particular, the electrochemical conditions, the solvent, the counterion, and monomers used during synthesis influence the electronic properties of the resulting polymer. 

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One of the main differences of electrodeposition paints with conventional water soluble paints is their lower solids and thus solvent content. A typical binder content is around 10%w, the amount of solvent approximately 5%. The rest, apart from pigmentation, is water. The influence of solvent in the early stages of binder/paint formulation is very similar to the effects described for conventional aqueous paints which is also started from an approx. 70% solids binder solution in coupling solvent(s). The choice of the solvent (blend) is, however, less influenced by its evaporation characteristics as the deposited paint film does not contain much water and is stoved after application. Of more importance are paint stability and electrical properties (conductivity, rupture voltage). 

However, the formation of monodisperse aqueous or organic drops in liquid-liquid systems is easily possible by the use of electrostatic fields [81]. Here, the applied voltage and thus the electric field at the capillary tip is the most significant parameter. This again is markedly influenced by the electrode and capillary geometry, as also by the electric properties (conductivity, permittivity, and charge relaxation time) of the liquids. 

Electrical properties Conductive Insulative to conductive (with fillers) Insulative to conductive... 

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