Rapid Room-Temperature Fabrication of Silk Fibroin Composite Hydrogels Based on TA-Fe₃O₄@MXene Self-Catalytic System for Flexible Sensing Applications

Acrylic acid (AA), acrylamide (AM), silk fibroin (SF), tannic acid (TA), ferroferric oxide nanoparticles (Fe₃O₄), and two-dimensional MXene nanosheets were used as raw materials. A conductive hydrogel marked as P(AA-co-AM)/SF/TA-Fe₃O₄@MXene was fabricated through one-pot free radical polymerization at room temperature in water/glycerol binary solvent. In this system, TA-modified Fe₃O₄ nanoparticles anchored on MXene nanosheets (TA-Fe₃O₄@MXene) served as functional fillers, and the whole fabrication process required no external energy supply. The composition, chemical states, and microstructure of the material were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The tensile and compressive mechanical properties and anti-fatigue performance of the hydrogel were evaluated using an electronic universal testing machine. Its wide-temperature stability was assessed by differential scanning calorimetry (DSC). The electrical conductivity and strain-sensing performance were investigated using a digital multimeter combined with a tensile apparatus. The hydrogel exhibits ultrahigh stretchability (1 640%), high tensile strength (292 kPa), high electrical conductivity (206.8 μS/cm), and excellent wide-temperature stability (−40 ℃ to 60 ℃). As a flexible strain sensor, it demonstrates high sensitivity (gauge factor (GF) is 5.92), good cycling stability, and real-time response to weak physiological signals such as joint motion and throat vibration, showing great potential for applications in flexible wearable electronics.