ON THE EFFECTS OF ELECTRICAL CONDUCTIVITY ON THE TRIBOELECTRIC BEHAVIOR OF A PDMS-BASED COMPOSITE MATERIAL

With the increasing demand for small and portable electronic devices, new energy conversion systems that can harvest energy from body motion and ambient environment are needed. Triboelectricity has recently become promising among the various energy conversion mechanisms because triboelectric devices can be small, flexible, and portable. The triboelectric output performance is closely related to the materials 'properties employed. In this study, the effect of electrical conductivity on the electrical output of a friboelectric device is investigated experimentally. Experiments are conducted using a vertical contact/separation mode with polydimethylsiloxane (PDMS) based material as one of the contacting materials. The electrical conductivity of PDMS is tuned by adding two different weight percent of multiwall carbon nanotube (CNT): 10wt% CNT and 20wt% CNT. The relationship between electrical conductivity and the triboelectric output performance is obtained by correlating the open circuit voltage (V-oc) and short circuit current (I-sc) with the different weight percent CNT-PDMS materials. A maximum V-oc of 98V and a maximum I-sc of 3.2 mu A were obtained with the 20wt% CNT-PDMS and Teflon pair; this increase is likely due to the combination of enhanced triboelectric polarity difference and electrical conductivity. The optimum external resistance was also measured for the different CNT-PDMS weight percent materials. The maximum triboelectric output power reached 180 mu W at 80M Omega for the 20wt% CNT-PDMS and Teflon pair.