One-Pot Construction of Carboxyl-Rich Silk Nanofiber/PDES Elastomers for Flexible Strain Sensors

Abstract Silk nanofibers (SNFs) are promising bio-based reinforcements for flexible sensors, but their integration into conductive elastomers is limited by complex processing and inefficient nanofibrillation. Here, a green one-pot strategy was developed to integrate silk carboxylation, nanofibrillation, and in situ photopolymerization within a hydrated oxalic acid/choline chloride deep eutectic solvent system. The resulting carboxyl-rich SNFs had an average length of 271.51 nm and a carboxyl content of 1.249 mmol g−1. Glycidyl methacrylate enabled formation of a physically and chemically dual-crosslinked SNF/poly(deep eutectic solvent) (SNF/PDES) elastomer, exhibiting 1080% strain, 1.28 MPa tensile strength, and 9.57 MJ m−3 toughness. As a strain sensor, the elastomer showed gauge factors of 0.861, 1.143, and 2.018 across 0−500% strain and stable output over 1000 cycles. This sustainable strategy provides a scalable route toward high-performance wearable sensing materials.