Conductance, polymer electrical properties measurement techniques

Although the electronic conductivity of an interphase that is present on an electrode can be related to various optoelectronic properties that are also measurable with spectroscopic techniques, the direct measurement of surface conductivities is not a spectroelectrochemical method. It is nevertheless a surface sensitive method that provides results closely related to those of other methods discussed in this book. Data on the electrosorption of alcohols on gold electrodes [45] or the electrode potential dependent conductivity of intrinsically conducting polymers [46] have been obtained with in situ surface conductivity measurements. Figure 4.4 shows the electrical resistance of a poly(2-propylaniline) film measured in situ under experimental conditions suppressing any influence of solution phase conduction. The influence of... 

Among the various interesting and useful properties of the new class of polymers, their switchable electrical conductivity has proven the most attractive to the community of chemists and physicists, and so it is understandable that these polymers are called conducting polymers. Much effort has been spent on measurements of their electrical conductivity and on determinations of the factors that affect its value [44,113,119,124,151,213,314,327,328,344,345,393 17]. The use of the conventional ex situ dc four-point method [44,393,398,399] or the ac impedance technique in a metal [polymer metal sandwich arrangement [119,124,410] for measurements of the conductivity of dry polymer samples is straightforward. However, the conductivities of dry polymers are affected by humidity and any gas present. Indeed, this is the property that is utilized in gas sensors. Conductivity can also be measured in situ, i.e., under controlled electrochemical and chemical conditions [151,394,395,397,400,402,406,408,417]. 

The control of dielectric permittivity and loss of solid polymers, through an understanding of the origins of their dipole relaxation and ionic conduction processes, is essential for their use in electrical insulation, in electrical/electronic circuits, and devices operated over wide power ranges. This article discusses dielectric properties and behavior of pol5uners and briefly describes measurement techniques and applications. 

Among the various interesting and useful properties of conducting polymers, their switch-able electrical conductivity has proven the most attractive. The use of the conventional dc four-prove method or the ac impedance technique in a metal-polymer-metal sandwich structure for measurements of the conductivity of dry polymer samples is straightforward. 

This study demonstrates, for the first time, the ability to manipulate the resistance of a conductive polymer without doping. Techniques were developed to allow blending conductive PANIS with commercially available polymers, and methods were devised to measure the resistance of the resulting blends. Polymer preparation, solvent selection and solvent removal have been shown to be critical in producing the desired physical, electrical and optical properties. 

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