Highly tough all-solid-state ionic conductors based on supramolecular deep eutectic polymers for stretchable wearable sensors

Abstract

All-solid-state ionic conductors (AICs) have become important materials for flexible electronic devices due to their ability to prevent liquid leakage and water evaporation. However, it is challenging to integrate high stretchability (>1000%) and high strength (>10 MPa) into a single AIC. Herein, a highly tough all-solid-state supramolecular deep eutectic polymer (ARCDEP) is constructed by incorporation of rigid hydroxyethyl cellulose (HEC) into an acrylic acid-betaine monohydrate (AA-Btm)-polymerizable deep eutectic solvent (PDES) to form a dense hydrogen-bonded crosslinking network that can effectively dissipate energy. The resulting ARCDEP exhibits high strength (13.90 MPa), ultra-stretchability (1737%), remarkable toughness (146 MJ m⁻³), transparency (>90%), and ionic conductivity (2.75 × 10⁻⁶ S cm⁻¹). In addition, ARCDEP possesses water-processable properties and crack resistance. Given its unique properties, the ARCDEP can be applied in a flexible electroluminescent device and a strain sensor. The strain sensor based on the ARCDEP exhibits reliable repeatability and a wide sensing range, making it suitable for applications in real-time human motion monitoring. This work establishes an effective strategy for designing high mechanical performance AICs while also facilitating the high-value utilization of low-cost cellulose.