Mechanically strong and folding‐endurance Ti3C2Tx MXene/PBO nanofiber films for efficient electromagnetic interference shielding and thermal management

Abstract Electromagnetic interference (EMI) shielding materials with excellent flexibility and mechanical properties and outstanding thermal conductivity have become a hot topic of research in functional composites. In this study, the “sol–gel‐film conversion technique” is used to assemble polyetherimide‐functionalized Ti 3 C 2 T x nanosheets ( f ‐Ti 3 C 2 T x ) with poly( p ‐phenylene‐2,6‐benzobisoxazole) (PBO) nanofibers (PNFs), followed by dialysis and vacuum drying to prepare f ‐Ti 3 C 2 T x /PNF films with lamellar structures. When the loading of f ‐Ti 3 C 2 T x is 70 wt%, the f ‐Ti 3 C 2 T x /PNF film presents optimal comprehensive properties, with an EMI shielding effectiveness (SE) of 35 dB and a specific SE/thickness ((SSE, SE/density)/ t ) of 8211 dB cm 2 /g, a tensile strength of 125.1 MPa, an in‐plane thermal conductivity coefficient ( λ ) of 5.82 W/(m K), and electrical conductivity of 1943 S/m. After repeated folding for 10,000 cycles, the EMI SE and the tensile strength of f ‐Ti 3 C 2 T x /PNFs films still remain 33.4 dB and 116.1 MPa, respectively. Additionally, the f ‐Ti 3 C 2 T x /PNF film also shows excellent thermal stability, flame retardancy, and structural stability. This would provide a novel method for the design and fabrication of multifunctional composite films and considerably expand the applications of MXene‐ and PNF‐based composites in the fields of EMI shielding and thermal management.