Solvent-toughened ultra-stretchable poly(ionic liquid) gels for multifunctional wearable bioelectronics

Mechanically robust flexible materials are highly desirable for wearable bioelectronics, yet achieving ultrahigh stretchability together with high toughness and stable electrical functionality remains challenging. Here, a solvent-toughened poly(ionic liquid) (PIL) gel is developed through a simulation-assisted solvent screening strategy combined with experimental optimization. An ionic liquid identified through multidimensional molecular simulations, together with PEDOT:PSS, establishes a dynamic ionic network and a conductivity-enhanced framework. The resulting PIL gel (PAE₂₀P_0.75) exhibits exceptional mechanical performance, including an ultrahigh fracture strain of 20,287.2%, a toughness of 33.2 MJ m⁻³, and a fatigue threshold of 1210 J m⁻², together with excellent self-healing capability, antifreezing stability, and long-term environmental durability. Benefiting from these integrated properties, the PIL gel enables multifunctional bioelectronic devices, including conformal bioelectrodes for electrophysiological monitoring (ECG, EMG, and EEG), highly stretchable strain sensors (GF 3.78), and triboelectric nanogenerators delivering a power density of 1.51 W m⁻² for self-powered sensing and energy harvesting. System-level demonstrations in a self-powered sleep respiration monitoring system and an intelligent assistive protection platform further highlight the potential of this material platform for real-time health monitoring and medical assistance. This work provides a rational design strategy for mechanically robust PIL gel and offers a promising material platform for next-generation wearable bioelectronics, intelligent health monitoring, and assistive technologies.