The functional gel materials have gained considerable attentions in flexible electronics and other applications. Therefore, in order to meet the applicability in real world environments, the development of versatile gels with excellent mechanical properties, superior swelling resistance and long-term high-temperature tolerance is essential for flexible electronic devices. Herein, a multifunctional EHMA-HPA-AA/IL gel is developed by incorporating 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ionic liquid ([BMIM][TFSI] IL) into a cross-linked copolymer matrix of isooctyl methacrylate (EHMA), 2-hydroxypropyl acrylate (HPA) and acrylic acid (AA). The EHMA as a hydrophobic component endow the gel with exceptional swelling resistance in water, seawater and acidic/alkaline (pH = 4 and 10) aqueous solutions for 14 days, and the [BMIM][TFSI] IL significantly strengthen the gel’s anti-drying capability and high-temperature adaptability (94% and 87% mass retention at 25 and 50 °C for 15 and 10 d). Meanwhile, by optimizing the content of HPA, the gel can achieve a high stretchability of 1391% and a good tensile strength of 121 kPa. Furthermore, benefiting from the excellent strain sensitivity (gauge factor = 1.66), wide strain range (0–600%) and reliable cyclic stability, the as-fabricated sensor based on the EHMA-HPA-AA/IL gel can not only precisely track the movements of aquatic animals and realize underwater communication, but also can real-timely record and transmit human motion signals even after being exposed to 50 °C for 10 d. In particular, the as-prepared gel exhibits a repeatable transparency-shifting behavior in water and dimethyl sulfoxide solvents and can be served as an ideal information storage and encryption platform.
