High Strength, Strain, and Resilience of Gold Nanoparticle Reinforced Eutectogels for Multifunctional Sensors

Eutectogels with inherent ionic conductivity, mechanical flexibility, environment resistance, and cost-effectiveness have garnered considerable attention for the development of wearable devices. However, existing eutectogels rarely achieve a balance between strength, strain, and resilience, which are critical indicators of reliability in flexible electronics. Herein, poly(sodium styrenesulfonate) (PSS)-modified gold nanoparticles (AuNPs) in eutectic solvents are synthesized, and PSS-AuNP reinforced polyacrylic acid/polyvinylpyrrolidone (SAu-PAA/PVP) eutectogel is successfully prepared. Through the coordination between AuNPs and the PAA/PVP polymer chains, the SAu-PAA/PVP eutectogel exhibits significantly enhanced tensile strain (946%), mechanical strength (3.50 MPa), and resilience (85.3%). The high-performance eutectogel was demonstrated as a flexible sensor sensitive to strain and temperature, and the AuNPs provided near-infrared sensing capabilities. Furthermore, SAu-PAA/PVP eutectogel inherits the benefits of ES, including anti-drying and anti-freezing properties (-77 °C). Moreover, the eutectogel is microstructured using a simple molding method, and the resulting hierarchical pyramid microstructured eutectogel functions as ionic dielectric layer in a pressure sensor. This sensor exhibits high sensitivity (37.11 kPa^-1), low detection limit (1 Pa), a fast response rate (36/54 ms), and excellent reproducibility over 5000 cycles, making them reliable and durable for detecting small vibrations, with potential applications in precision machinery, aerospace, and buildings.