Mechanically Strong, Wet Adhesive, and Self-Healing Polyurethane Ionogel Enhanced with a Semi-interpenetrating Network for Underwater Motion Detection.

The gel-based sensors have developed rapidly in recent years toward multifunctionality. However, there are still some challenges that need to be solved, such as poor mechanical properties and inaccessibility to wet or water environments. To address these issues, we have developed an ionogel with a semi-interpenetrating network structure by adopting poly(vinylidene fluoride- co -hexafluoropropylene) as the linear non-cross-linked network, a double-bonded ionic liquid and double-bonded capped polyurethane as the cross-linked network, and an ionic liquid as the conductive media. The obtained ionogel exhibits tunable mechanical properties (3.67-8.76 MPa) and excellent sensing properties (IG-20, GF = 8.2). The superb environmental stability and self-healing properties of the ionogel were also demonstrated. Meanwhile, adhesion, self-healing, and sensing performance were guaranteed for underwater due to the presence of a large number of C-F bonds. We strongly believe that this ionogel with excellent mechanical properties and underwater communication is expected for monitoring the health of the human body and information transmission in the future.