Self-Adhesive, Antifreezing, and High Resilience Biobased Ionogel as a Flexible Strain–Temperature Bimodal Sensor

Abstract

Biobased ionogels have become more desirable, because they can improve the safety and sustainability of flexible wearable devices. However, common biobased ionogels prepared with small-molecule cross-linkers can hardly satisfy the requirements of adjustable mechanical properties, strong adhesion, and fatigue resistance. Herein, a chemical cross-linked gelatin/oxidized microcrystalline cellulose ionogel (GEL/OMCC) was fabricated via a simple heating-evaporation-induced method. The obtained ionogel possessed good electrical conductivity (4.951 mS/cm, room temperature), high resilience, and extreme temperature tolerance (−50 to 240 °C). Meanwhile, the adhesive strength of the ionogel to Cu foil was up to 61 kPa due to the presence of a large number of hydroxyl bonds in biomaterials. Additionally, the ionogel demonstrated high electromechanical performance, temperature responsiveness, and rapid responsiveness (74 ms), rendering it as an ideal candidate to be utilized as a strain-temperature bimodal sensor in flexible intelligent electronics.