Transparent, mechanically robust, and ultrastable ionogels enabled by hydrogen bonding between elastomers and ionic liquids

Abstract

Nonvolatile ionogels have recently emerged as promising soft electrolyte materials for use in flexible electronics. However, it remains challenging to fabricate highly robust and stable transparent ionogels. Here, high-performance ionogels with excellent transparency, mechanical robustness, and ultrahigh stability are designed by virtue of hydrogen bonding between poly(ethyl acrylate)-based elastomers and room-temperature ionic liquids (ILs). Through rationally tuning the chemical structures of ILs and thus achieving good compatibility of ILs with elastomers, the transparent hydrophobic ionogels exhibit super-strong mechanical properties (favorable elasticity of 15–484 kPa, ultrahigh stretchability of more than 5000%, and record-high fracture toughness of up to 4.7 kJ m⁻²) and high stability (high thermal stability, high voltage stability, air stability, humidity resistance, strong self-adhesion, and non-corrosive stability). In particular, it is demonstrated that a skin-like sensor fabricated using the ionogel directly not only exhibits outstanding durability (10 000 cycles at 100% strain), but is also capable of operation under harsh environmental conditions, including high vacuum, high/low temperatures, and high humidity. It is believed that this work provides new prospects for sophisticated wearable optoelectronic devices.