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

Abstract

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