Highly Stretchable, Transparent, Solvent-Resistant\nMultifunctional Ionogel with Underwater Self-Healing and Adhesion\nfor Wearable Strain Sensors and Barrier-Free Information Transfer

Ionogels with excellent deformability, high ionic conductivity,\nand a sensitive stimulus response have been widely used and rapidly\ndeveloped in flexible wearable systems. However, previously reported\nionogels are mainly limited to atmospheric environments applications\nand have difficulty meeting the requirements of solvent-resistant,\nself-healing, and adhesion properties in underwater environments.\nHerein, a multifunctional ionogel capable of underwater applications\nis prepared by one-step photoinitiated polymerization of a fluorine-containing\nmonomer (2,2,3,4,4,4-hexafluorobutyl acrylate, HFBA) and acrylic acid\n(AA) in a hydrophobic ionic liquid ([EMIM][TFSI]). The dynamic physical\ninteractions of hydrogen bonds and ionic dipoles endow the ionogel\nwith remarkable transparency, tunable mechanical properties, and underwater\nself-healing properties. Moreover, the fluoropolymer matrix offers\nhigh resistance to water and various solvents and exhibits strong\nunderwater adhesion on different substrates. Thus, the sensor based\non the ionogel exhibits excellent sensing properties, including high\nsensitivity, fast response, and superior durability. In particular,\nthe ionogel can be used as a wearable underwater sensor to perform\nbarrier-free information transfer. This study provides a design idea\nfor the development of underwater flexible strain sensors.