A Flexible and Adhesive Strain Sensor Based on Deep Eutectic Solvents for Deep Learning-Assisted Signal Recognition

Flexible wearable electronic devices have garnered significant interest due to their inherent properties, serving as replacements for traditional rigid metal conductors in personal healthcare monitoring, human motion detection, and sensory skin applications. Here, we report a preparation strategy for a self-adhesive, ultrahigh stretchable DGel based on poly(acrylic acid) (PAA). The resulting DGel exhibits a high tensile strength (approximately 2.16 MPa) and an ultrahigh stretchability (approximately 5622.14%). More importantly, these meticulously designed DES gels demonstrate high signal recognition capabilities under strains ranging from 1 to 500%. DGel also shows excellent cyclic stability and durability (5000 cycles at 100% strain), exhibiting a superior electromechanical performance as a strain sensor. The ultrahigh strength of DGel is attributed to the synergistic effects of chemical and physical cross-linking within the gel. Additionally, DGel can be effortlessly assembled into wearable sensors. By integration of flexible sensing with deep learning, the fabricated touch recognition system achieves an identification accuracy of up to 99.33%. This advancement offers new insights into designing novel gels for a variety of applications, including tissue engineering, sensing, and wearable electronic devices.