Sliding Cyclodextrin Molecules along Polymer Chains to Enhance the Stretchability of Conductive Composites

Abstract

The demand for stretchable electronics with a broader working range is increasing for wide application in wearable sensors and e-skin. However, stretchable conductors based on soft elastomers always exhibit low working range due to the inhomogeneous breakage of the conductive network when stretched. Here, a highly stretchable and self-healable conductor is reported by adopting polyrotaxane and disulfide bonds into the binding layer. The binding layer (PR-SS) builds the bridge between polymer substrates (PU-SS) and silver nanowires (AgNWs). The incorporation of sliding molecules endows the stretchable conductor with a long sensing range (190%) due to the energy dissipation derived from the sliding nature of polyrotaxanes, which is two times higher than the working range (93%) of conductors based on AP-SS without polyrotaxanes. Furthermore, the mechanism of sliding effect for the polyrotaxanes in the elastomers is investigated by SEM for morphological change of AgNWs, in situ small-angle x-ray scattering, as well as stress relaxation experiments. Finally, human-body-related sensing tests and a self-correction system in fitness are designed and demonstrated.