The fretting characteristics of intrinsically conducting polymer contacts

The study of fretting and the associated corrosion has always been an important focus for many researchers involved in the field of electrical contacts. This phenomenon is often the result of subjecting contacts to thermal cycling and vibration. In many cases, it is also the direct cause of failure in connector systems and hence leads to adverse consequences for numerous applications. With the increasing interest in using conducting polymers as possible alternatives for contact materials, the effects of fretting degradation is analysed to establish the reliability of this novel technology. The intrinsically conducting polymers (ICPs) used in the experiments are poly(3,4-ethylenedioxythiopene)/poly(4-styrenesulfonate) and its blends, which have conductivity levels in the order of 10^-2 S.cm^-1 and easy processing capabilities. The ICPs are spin-coated or drop-coated and cured onto copper surfaces. The samples are subsequently placed in two types of fretting apparatus to carry out independent thermal cycling and vibration measurements. The surface profiles of the ICP coats are also recorded by an optical confocal system to observe the occurrence of physical deformation. In this paper, the results presented are the initial studies on employing ICP contacts to eliminate or minimise fretting. It has been found that the resistance decreases as temperature and the number of fretting cycles increase. Furthermore for the same polymer blend, the type of coating technique also affects the output resistance.