Low‐Molecular‐Weight Supramolecular‐Polymer Double‐Network Eutectogels for Self‐Adhesive and Bidirectional Sensors

Abstract Ionic conducting eutectogels have attracted enormous attention as an alternative to the conventional temperature‐intolerant hydrogels and costly ionic liquid gels in constructing flexible electronic devices. However, current eutectogels prepared via cross‐linked polymer or low‐molecular‐weight gelators suffer from limited stretchability and insufficient surface‐adaptive adhesion. Herein, a low‐molecular‐weight supramolecular network is introduced into a covalent polymer network in a eutectogel architecture, and a novel supramolecular‐polymer double‐network (SP‐DN) strategy is demonstrated to fabricate conductive SP‐DN eutectogels with high stretchability (>4000% elongation) and toughness (≈800 J m −2 ), as well as self‐healing, self‐adhesive and anti‐freezing/anti‐drying characteristics. These unique features lead to the successful realization of SP‐DN eutectogels in wearable self‐adhesive strain sensors, which can conformally deform with the skin and dynamically monitor body movements with high sensitivity and long‐term stability over a wide temperature range (−40 to 60 °C). Furthermore, the strain sensors can accurately detect body movements along two opposite directions (bend up or bend down), which are rarely reported in the literature. Distinct from the widely explored polymer double‐network (P‐DN) hydrogels, the developed SP‐DN eutectogel platform is capable of well‐regulating molecular‐scale noncovalent and covalent interactions, providing a paradigm for the creation of smart soft materials with versatile performance and high environmental adaptability.