Dynamic Adaptive Wrinkle‐Structured Silk Fibroin/MXene Composite Fibers for Switchable Electromagnetic Interference Shielding

Abstract Flexible and dynamic adaptive conductive composite fibers are demanded for functional fabrics and wearable devices, yet the weak interfaces often impair the critical performances for complicated application scenarios. Here, a general and scalable strategy is proposed to construct robust and reversible wrinkle structures on regenerated silk fibroin (RSF) fiber with 2D nanomaterials (i.e., MXene, graphene) by wet‐spinning technique. The dynamic conformation transition of silk fibroin and the core‐shell modulus mismatching together are responsible for the formation of wrinkled structures. Then, it effectively optimizes the interfaces between the assembled nanomaterials and fiber substrate, which significantly reinforce the fibers, complete conductive pathways, and endow exceptional robustness and durability. The MXene‐based fiber shows a high conductivity of ≈1125 S cm −1 , far superior tensile strength of 214.3 ± 6.8 MPa and toughness of 15.2 ± 1.5 MJ m −3 as compared to RSF fiber. More interestingly, the transformable wrinkled structure further modulates surface behaviors and properties of the fibers, such as the switchable shielding performances from “off‐state” to “on‐state” induced by humidity. Additionally, the integration of mechanical flexibility and outstanding capacitance (≈829 F cm −3 ) further expects the great promise of MXene‐based fibers for self‐powered wearable electronics, and intelligent fabrics.