Ultra-stable ionogels based on hydrogen networks with broad temperature, environment, and long-term stability

Abstract

Ionogels with broad temperature, environment, and long-term stability are desirable in intelligent flexible electronics. Herein, we have developed a novel ultra-stable ionogel through hydrogen bonding between the amphiphilic ionic liquid--1-ethyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([EMIM][NTf]) and butyl acrylate (BA)-ethyl ethoxyethyl acrylate (EO) copolymer (P(BA-co-EO)). The ionogel demonstrates high decomposition voltage, strong adhesion stability, non-corrosive stability, and cyclic strain sensing stability (500 cycles at 120 % strain). Additionally, it exhibits broad temperature and environment adaptability, capable of stretching up to 7 times at −20 °C, maintaining consistent weight after 30 days of storage in extreme environments such as low/high temperatures (−20∼100 °C), high vacuum (6 × 10 Pa), and underwater (without additional sealed packaging), while also maintaining electrophysiological monitoring at −20 °C or 100 °C. Most importantly, the ionogel without sealing can self-adhere to the human skin for continuous and high-quality electrophysiological monitoring for 1 month under daily life conditions. We have utilized the ionogel to fabricate an ionic skin with multifunctional sensing capabilities for strain, pressure, and temperature, which has been successfully employed in human motion and pressure detection. It is believed that ionogels with long-term stability will pave the way for developing next-generation intelligent flexible electronics in future research endeavors.