Mechanically Robust, Temperature Tolerant, Adhesive, Self-Healing, and Transparent Supramolecular Eutectogels as Flexible Sensors

Graphical PDES-SS eutectogels were prepared by integrating sericin (SS) with deep eutectic solvent composed of ChCl and AA, and subsequent photopolymerization. SS with numerous functional groups constructed supramolecular network structure with PAA polymers, enabling the eutectogels with attractive mechanical, self-adhesive, and self-healing performances and temperature tolerance for sensor in human motion monitoring. Ionic conductive gels have a promising prospect in flexible sensors due to the stretchability, tunable mechanical properties, and ionic conductivity, but inhibited by the integrations of multifunctionality, environmental stability, and high sensitivity in practical applications. Herein, novel sericin (SS)-derived supramolecular eutectogels were designed and fabricated via simply one-step photopolymerization of deep eutectic solvent (DES). In this strategy, the integration of SS with numerous functional groups (─COOH, ─NH 2 , and ─OH) constructed supramolecular network structure with multiple hydrogen, ionic, and electrostatic interactions. Such supramolecular eutectogels showed superb transparency of 93% transmittance and mechanical properties. When the content of SS was 0.4 wt%, the tensile strength, strain, and toughness of the resultant PDES-SS eutectogels were high to 4.02 MPa, 1703%, and 3.76 MJ/m 3 , increment by 1.9, 0.5, and 2.0 times than those of PDES without SS, respectively. Owing to the constructed reversible supramolecular network, the PDES-SS eutectogels displayed excellent self-healing and self-adhesive ability. Importantly, the remarkable mechanical robustness, transparency, self-adhesion, and conductivity can be maintained in a wide temperature range (−40 °C–60 °C), contributing to the application as high-performance flexible sensors. Obviously, PDES-SS eutectogels could precisely and stably detect strain as well as monitor human movement and physiological signals in real-time.