Dual-Network Toughening of Aramid Nanofiber/MXene Core–Shell Fibers with Boosted Mechanical and Electrical Performance

MXene-based fiber electronics have gained significant attention due to their superior performance. However, the potential applications are limited by drawbacks, including poor spinnability, inferior mechanical properties, and weak stability during practical applications. In this study, a core–shell fiber electronic was prepared via coaxial microfluidic spinning. Specifically, a dual-network architecture composed of an aramid nanofiber (ANF) entanglement network and an ANF-MXene hydrogen-bonding network was introduced in the core, while a protective encapsulation of ANFs was constructed in the shell. The MXene nanosheets were interconnected by the entangled ANFs and anchored via the ANF-MXene hydrogen-bonding network, leading to improved spinnability of the MXene suspension. Consequently, the resultant ANF/MXene fiber (AMF) exhibited enhanced mechanical properties. By incorporating thermochromic microcapsules into the shell layer, the AMF showed proof-of-concept thermochromic temperature indication and Joule-heating functions. Moreover, the enhanced stability of the ANF-MXene hybrid network holds significant potential in applications as stable strain sensors, enabling the precise detection of small deformations. This research presents a one-step fabrication method for high-performance fiber electronics with good mechanical properties, significantly broadening the application prospects of MXene-based electronics.