Robust and highly conductive silk fibroin fibers boosted by poly(ionic liquid)-mediated nanocarbon dispersion for multimodal sensors

Flexible electronic sensors have demonstrated significant application potential in fields such as artificial intelligence and healthcare, attracting considerable attention and research from the industry. Silk fibroin (SF) emerges as a promising candidate material for flexible electronics due to its biocompatibility, mechanical flexibility, and tunable nanostructure. However, its poor electrical conductivity limits practical applications. In this study, imidazole-based polyionic liquids (PIL) were used as an intermediate medium between silk fibroin (SF) and nanocarbon materials (NCs), successfully preparing conductive silk fibroin materials. Scanning electron microscopy (SEM) observations revealed that NCs were successfully and uniformly attached to the SF surface, and PIL effectively addressed the agglomeration issue of NCs, maintaining their original morphology while reducing particle size. The resulting NCs@SF materials exhibit high electrical conductivity (1.6 mS/mm), excellent mechanical durability (95 % conductivity retention after 1000 bending cycles), and multi-response capabilities to strain, pressure, temperature, and humidity. Furthermore, due to its biocompatibility advantages, this material can be developed into wearable sensors for detecting human respiratory rate, bending angle, and laryngeal vocalization status.