Highly stretchable, self-healing, and adhesive polymeric eutectogel enabled by hydrogen-bond networks for wearable strain sensor

Abstract

Compared with traditional hydrogels and ionic liquid gels, ionic conducting eutectogels have the advantages of temperature resistance, low cost, and biocompatibility, showing great potential in wearable stress pressure sensors and bioelectrodes. However, current eutectogels prepared from cross-linked polymers suffer from poor self-healing properties and insufficient surface-adaptive adhesion. In this work, we highlight for the first time the potential of monomers containing hydrogen-bond acceptor groups, and the obtained polymer can form hydrogen-bonding networks with deep eutectic solvents (DESs), thus endowing the eutectogel with self-healing and adhesive properties. These polymeric eutectogels were produced through polymerizing 1-vinylimidazole in emerging DES. The resultant eutectogels exhibited super-stretchability (approximately 2300% elongation), self-healing ability, and adhesion. Due to the unique properties of deep eutectic solvents, these eutectogels also exhibited high ionic conductivity and antifreeze/anti-drying properties. In addition, these properties lead to the successful realization of the eutectogels in conformal strain sensors to accurately detect human motion under a wide temperature range (−30 to 60 °C). The findings of this work would provide a promising strategy for the design of functionally integrated soft materials.