Highly thermally stable and flexible conductive film electrodes based on photo-responsive shape memory polyimide

Abstract

Conductive polyimide (PI) film electrodes, which combine the electrical conductivity of silver nanowires (AgNWs) with multi-stimulus response properties, are promising for smart devices, such as actuators, remote sensing circuits, intelligent garments, and smart flexible robots. The flexible electrodes are fabricated using shape memory polyimide as the substrate. In addition, a thermally cured liquid photopolymer, SR 368D, was used as a transition layer and AgNWs served as the conductive layer (denoted as AgNW/SR/PI electrode). The AgNW/SR/PI electrodes exhibited a low resistivity of ∼1.3 Ω sq−1 because of the high conductivity of the AgNWs. Integrating the high strength of PI films with AgNWs gave the electrodes highly conductive and stable properties. The electrodes were able to maintain a low resistivity of ∼1.5 Ω sq−1 even after 2000 bending/unbending cycles and retained ∼1.8 Ω sq−1 after 2000 adhesion/peeling cycles. Moreover, the AgNW possessed conductivity and infrared absorption, and the flexible electrodes recovered the initial shape under the effects of Joule heating and photo-thermal trigger by an electric stimulus and photo stimulus.