Highly transparent ionogel for wearable force sensor and 3D printing

Hydrogel-based electronics have gained comprehensive research interest in the field of wearable sensory device engineering owing to their electrical and mechanical properties, biomimetic features and biocompatibility. However, unlike traditional electronics with well-established manufacturing technologies, hydrogel electronic still need to develop durable force sensing, high transparency, favorable biosafety and low-cost preparation process. Herein, an ionic hydrogel electronics was reported by introducing interpenetrative polymers into natural polysaccharide matrix network via a photocurable additive manufacturing method. The obtained ionogel displays excellent mechanical properties including high mechanical strength of 160 kPa at a tensile strain of 640 %, and durablility over 1000 compression cycles without plastic deformation, while maintaining biocompatibility and transparency (91.6 %, 1 mm). By virtue of its excellent sensing abilities as well as remarkable reproducibility, the assembled ionogel-based wearable sensor are capable to precisely monitor subtle motions in facial expression and large joint bending. Crucially, the incorporation of polymers into bio-based supporting matrix yield promising 3D printed materials with integrated strain sensors, providing significant flexibility for the design and preparation of the next-generation flexible devices.