UV-induced multifunctional ionogel with robust underwater adhesion for long-term underwater sensing

s Ionogels, as a functional material with ionic conductivity, flexibility and environmental stability, are widely used in the field of flexible sensors. However, conventional ionogels often face problems such as insufficient adhesion and unstable sensing performance in wet or underwater scenarios. Hence, this study prepared a versatile ionogel sensor exhibiting environmental stability and strong adhesion, suitable for underwater sensing, via UV-initiated polymerization of tert-butyl acrylate (TBA), methoxyethyl acrylate (MEA), and 2,2,3,4,4,4-hexafluorobutyl acrylate (HFBA) monomers in 1-butyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide ([BMIM][TFSI]) as the dispersion medium. Hydrophobic TBA and HFBA monomers effectively block water molecule penetration into the gel, granting excellent anti-swelling properties (mass retention > 90 % in various solvents). Fluorine-containing segments in the gel enhance thermal stability (only 2 % mass loss was observed after 21 days at 80 ℃) and impart underwater self-healing ability and high adhesion strength. The ionic liquid is uniformly distributed in the three-dimensional network structure of the gel, providing excellent electrochemical performance and endowing the gel with rapid response capability (response time of only 3 ms). This work provides a promising approach for the application of ionogel sensors in wearable devices in humid environments.