Study of Temperature Change and Vibration Induced Fretting on Intrinsically Conducting Polymer Contact Systems

The study of fretting and the associated corrosion has always been a key focus for many researchers involved in the field of electrical contacts. This phenomenon usually occurs when subjecting contacts to thermal cycling or vibration. Often, it is also the direct cause for failure in electrical connector systems and eventually leads to undesirable consequences in numerous applications. With an increasing interest invested in developing new contact materials, conducting polymers are explored as possible alternatives to improve reliability by reducing the influence of fretting degradation. In this paper, the intrinsically conducting polymers (ICPs) used in the experiments are poly(3,4-ethylenedioxythiopene)/poly(4-styrenesulfonate) and its blends with different weight ratios of dimethylformamide. They have conductivity levels reaching the order of 10-2S·cm-1 and possess easy processing capabilities. Contact samples are fabricated by spin-coating or drop-coating ICP onto copper surfaces to form conducting polymer contact interfaces. These samples are then placed in two different types of fretting apparatus and tested independently using the thermal cycling and vibration procedures. Field vehicles tests are also conducted. The initial experimental results reveal that the resistance decreases as temperature and the number of fretting cycles increase. Furthermore, for the same polymer blend, the type of coating technique and the coating thickness also affect the output resistance.