Strain-Sensitive Double-Network Organogel With Strong Adhesion for Movement Monitoring

Abstract

Conductive organogels, as a class of soft materials, have demonstrated great application potential in the field of flexible electronics. However, they often suffer from several drawbacks, including low transparency, poor mechanical properties, low sensitivity, and weak adhesion. In this work, a highly adhesive and stretchable double-network organogel is constructed by the interpenetration of a nanofiber network self-assembled from 1,3:2,4-dibenzylidene sorbitol (DBS) and tough polyacrylamide (PAM) chains in glycerol. Lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) is incorporated to modulate the ionic conductivity of the gel, forming multiple ionic and intermolecular interactions within the gel network. The DBS/PAM-Li conductive organogel exhibits high and durable adhesion strength to various substrates, as well as good optical transparency (92% transmittance at a thickness of 1.45 mm). Furthermore, when assembled into a strain sensor, the DBS/PAM-Li organogel exhibits a high gauge factor of 8.72, a fast response time of 133 ms, and the capability to detect both small (with a low detection limit of 0.25% strain) and large deformations. This material can be used to monitor human motion, expanding the applications of flexible gel materials in the field of wearable electronics.