Facile Fabrication of Highly Stretchable, Stable, and Self-Healing Ion-Conductive Sensors for Monitoring Human Motions

Abstract

Ionic liquid (IL)-based conductive elastomers have recently emerged as promising stretchable electrodes for applications in flexible electronic devices because of the interesting features of ILs. However, conventional IL-based elastomers suffer from low mechanical properties, instability in the ambient environment, and lack of self-healability. Herein, highly stretchable, stable, and self-healable IL-based conductive elastomers PnBA/SiO2/PVI (Cu2+, [EMIM]+[BF4]−) were designed and facilely fabricated by one-pot Pickering emulsion polymerization. The Pickering emulsion is composed of the continuous phase of n-butyl acrylate, the dispersed phase containing vinylimidazole, copper acetate and IL ([EMIM]+[BF4]−), and the surfactant vinyl-SiO2. The fabricated materials feature an elastic matrix with microionogel particles embedded in it. The system is chemically and physically cross-linked via vinyl-SiO2 and Cu2+-imidazole coordination interaction, respectively. Such a rational design endows the resulting elastomers with a wide range of properties, including good conductivity, high stretchability, excellent mechanical properties, and self-healability. Besides, owing to this unique structure, they display high stability and their weight and electrical aspects remain almost unchanged in open air and a wide temperature range (30, 50, and 100 °C). Utilizing as flexible sensors, the as-prepared elastomers are able to accurately monitor real-time human motions via converting external stimuli into stable and repeatable signal variations during deformations.