Stretchable and Healable Conductive Elastomer Based on PEDOT:PSS/Natural Rubber for Self-Powered Temperature and Strain Sensing

Self-powered elastic Conductors based on thermoelectric materials with the ability to harvest energy from the living environment are considered as important for electronic devices under off-grid, maintenance-free, or unfeasible battery replacement circumstances. Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) is perhaps the most well-known organic conductor. However, the application of PEDOT:PSS in flexible devices is limited by its brittleness and various unrecoverable properties under strain. Various polymer blends based on water-soluble polymers and PEDOT:PSS have been prepared. Nevertheless, they fail to illustrate good balance between electrical conductivity and mechanical performance due to various issues, including the phase morphology with PEDOT:PSS as the dispersed phase; thus, the formation of a conductive network between PEDOT:PSS is prohibited. In this study, PEDOT:PSS is incorporated into natural rubber (NR), with NR as the dispersed phase. For 10 wt % PEDOT:PSS–NR composite films doped with dimethyl sulfoxide (DMSO), the conductivity was up to 87 S/cm and the elongation at break was maintained at 490%. More importantly, self-powered temperature- and tensile strain-sensing abilities were also realized. Furthermore, it is also demonstrated that most of the unrecoverable strain and conductivity under cyclic tensile strain could be healed by water and phosphate-buffered saline (PBS) post-treatment. This work provides interesting insights for preparing healed and stretchable self-powered electronic sensors.