One stroke for many uses: Facile constructing hydrogel sensors with strong anti-damage, anti-freezing, anti-drying, cancer killing ability and biocompatibility

Abstract

Conductive hydrogels promise a great application prospect in future flexible sensor areas. However, great challenges still remain in successfully constructing a green hydrogel sensor with the efficient synergy of various advantages simultaneouly using green starting chemicals via an one-step green procedure. Interestingly, here, the challenges were overcome via a superhydrogen-bond networks (SHBNs) strategy developed by which a novel PVA/TA/GO hydrogel was readily constructed and successfully synergized robust mechanical properties (e.g. endure an 80 kg boy), strong anti-damage (not fractured at a 300% strain for a hydrogel with a hole pre-drilled), anti- freezing (still has enough strong mechanical performances, good electrical conductivity, strain sensitivity and stable signal output capacity even at extremely low temperatures on performing real-time tasks) and anti-drying (not dried after exposure to air for three months, and still retain excellent mechanical/anti-freezing performances similar to original hydrogel). The easy construction (only one-step freezing) of the hydrogel, and significantly strengthened mechanical properties and excellent anti-freezing/anti-drying abilities mainly result from the SHBNs between the hydroxyls on PVA and the hydroxyls on TA/GO/glycerol. Moreover, no toxic/volatile starting chemicals were used in the preparation and also discharged into the surrounding environment. More attractingly, the hydrogel possesses cancer killing ability while biocompatibility. Another impressive charm is that after being assembled into a hydrogel sensor, it can satisfactorily recognize various motion signals. Therefore, this SHBNs strategy, collecting diverse outstanding advantages in one, opens up a new avenue for designing new high-performance hydrogels for applications regardless of in an extremely low temperature or a dry environment.