A sandpaper assisted micro-structured polydimethylsiloxane fabrication for human skin based triboelectric energy harvesting application

This paper reports a sandpaper based inexpensive and simple fabrication process of functional micro-structured PDMS (Polydimethylsiloxane) film to be used as a triboelectric layer. The micro-structured PDMS film was replicated directly from the low surface energy sandpaper template without the use of any surfactant coating, high vacuum or high-pressure equipment. A human skin and PDMS interaction based triboelectric generator (TEG) is demonstrated using as-fabricated micro-structured PDMS film. In our proposed TEG harvester, electrical energy is produced by continual contact-separation processes between PDMS and human skin. Four different micro-structures were compared with flat film and the influences of surface structures on the electrical output of the harvester are systematically studied. Results show that the existence of micro-structures on the PDMS films effectively enlarges the contact area and provides more surfaces for charge storage and hence improve the output performance of TEG. The as-fabricated prototype can produce peak-peak open-circuit voltage up to 103 V and 4.8 mW/m² of peak power density, which is exceptionally attractive for the fabrication of self-powered and portable devices. This stable PDMS film with functional micro-structures, which is fabricated using reusable sandpaper template facilitates robust and large-scale fabrication, and has potential for future applications in triboelectric energy harvesting devices.