Ultrastrength High-Sensitivity Poly(acrylic acid)-Based Deep Eutectic Solvents Gel for Wearable Strain Sensing and Human Health Monitoring

Flexible sensing materials play a pivotal role in realizing human–machine interfaces, biomedical electronic applications, and robust wearable sensors. Deep eutectic solvents (DES), as eco-friendly alternatives to ionic liquids, have garnered considerable attention. However, achieving both high strength and sensitivity in DES gel (DGel) poses a formidable challenge. In this study, we present a method for producing DGel with high strength and sensitivity, utilizing poly(acrylic acid) (PAA). The resulting DGels demonstrate a satisfactory tensile strength (approximately 17.17 MPa) and impressive elongation (approximately 329.2%). Most notably, these meticulously engineered DGels exhibit a notable high sensitivity (GF = 16.14) across a strain range of 0.1% to 200%. The DGel also exhibits adequate cyclic stability and durability, making them ideal candidates for strain sensors with outstanding electromechanical performance. The exceptional strength of DGel arises from a combination of chemical and physical cross-linking within the gel structure. Additionally, DGel can be easily integrated into wearable sensors, holding substantial potential for the development of next-generation high-performance flexible electronic devices.