Anti-fatigue, self-bonding, adhesive gels for easy-to-prepare 3D stacking flexible electronics†

Abstract

Hydrogels have emerged as promising candidates for flexible electronics applications. However, their inherent water loss characteristics significantly compromise performance stability during operation, thereby limiting their practical applications. In this study, we developed a novel polymer gel by substituting water with polyethylene glycol-modified silicone oil. This polymer gel maintained the desirable softness while exhibiting superior stability under ambient conditions. The gel exhibited tunable mechanical properties with an adjustable modulus compatible with human skin tissue. Due to its low energy dissipation characteristics, the gel could sustain more than 1000 stretching cycles without notable performance deterioration. The material's exceptional self-bonding properties facilitated the fabrication of flexible electronic devices through simple stacking processes, while its strong adhesion enabled reversible skin attachment. The gel's electrical insulation properties ensured reliable operation of flexible circuits, and its compatibility with liquid metal enabled the fabrication of strain-sensitive flexible circuits. When applied as wearable sensors, these devices demonstrated stable skin adhesion and maintain reliable operation for over 30 days under ambient conditions. Moreover, the gel's self-bonding characteristics enabled the construction of multilayered three-dimensional flexible circuits, leading to enhanced strain sensitivity and device miniaturization. These comprehensive performance advantages, combined with exceptional stability, position this polymer gel as a promising material for advancing flexible electronics, particularly in the development of compact, high-performance flexible wearable devices.