Salt-mediated triple shape-memory ionic conductive polyampholyte hydrogel for wearable flexible electronics

Abstract

Wearable flexible electronics (WFEs) made of multifunctional hydrogels provide an approach for monitoring the human health such as human activities and human sweat. However, it is still necessary to develop a stimulus-responsive hydrogel sensor with the shape-memory effect (SME) to broaden the applications. Herein, we designed and fabricated a type of supramolecular polyampholyte hydrogel with salt-mediated triple SME, ionic conductivity (0.24–3.06 S m⁻¹), high stretchability (up to 1500%) and self-healing property (up to 70%), which can be applied as shape-memory sensor and strain sensor. The SME endowed the sensors with the ability to detect the concentration changes in a saline solution by visual shape transformation. The conductivity caused the sensors to react with an instant electric signal when they detected human motion, while the stretchability allowed the sensors to bear large-scale mechanical deformation. The spontaneous self-healing and self-adhesive capabilities gave the sensors higher reliability, extended lifetime, and good attachment to human skin. Therefore, this multifunctional hydrogel can be a good candidate for precisely and conveniently monitoring the human health.