A Transparent, Tough, Highly Stretchable and Self-Adhesive Zwitterionic Dual-Network Eutectogel for Wearable Flexible Sensors

Abstract

Eutectogels possess significant potential for use in wearable flexible sensors due to their low volatility, chemical stability, and high ionic conductivity. However, most eutectogels face challenges such as intransparency, non-adhesion, and limited mechanical strength, which hinder their practical applications. In this study, we designed and successfully constructed a novel zwitterionic dual-network (DN) eutectogel to address these limitations and analysed the interactions within the polymer by molecular dynamics. This eutectogel comprises a pre-polymerized network of [2-(Methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl) (DMAPS) and physically crosslinked acrylic acid-N-(2-hydroxyethyl) acrylamide copolymers (p(AA-co-HEMAA)). The DN eutectogels exhibit exceptional properties, including high strength (0.569 MPa), elongation at break (637%), toughness (2.529 MJ m^-3), and high transparency (~89%). Additionally, they possess good adhesion and stability. Flexible sensors with high sensitivity, a wide detection range, and excellent stability were fabricated from these eutectogels and tested with various applications, including limb motion detection, handwriting recognition, and Morse code translation. This study not only showcases a high-performance eutectogel-based sensing material but also paves the way for the development of multifunctional wearable devices in the future.