(200d) Electromagnetic Interference Shielding Performance of Ti3C2Tx Mxene/Polyelectrolyte Fibers and Composite Laminates

Due to its tunable surface chemistry, excellent electrical conductivity, and mechanical properties, Ti₃C₂T_x (T= OH, O, F, Cl) MXene is a promising material for designing high-performance electromagnetic interference (EMI) shielding. In addition to the excellent performance of individual MXene nanosheets for EMI shielding, the morphologies of their assemblies highly impact the shielding effectiveness. Among different MXene assemblies, fibers have gained special attention due to the feasibility of shaping them into different forms and arrangements. The thin 2D geometry and the strong repulsion among the nanosheets create liquid crystalline phases in the dispersion of MXene nanosheets and provide the opportunity to fabricate highly aligned MXene-based fibers. In this work, MXene-based fibers are designed by the controlled assembly of poly(allylamine hydrochloride) (PAH), a positively charged polyelectrolyte, and the negatively charged MXene nanosheets at an interface. In fact, the complexation of PAH chains and the MXene nanosheets results in assemblies comprising interconnected MXene nanosheets that can be drawn in the form of fibers. Our results show that MXene/PAH fibers exhibit a high electrical conductivity of > 3000 S/cm and an excellent EMI shielding effectiveness of about 30 dB in the X-band frequency regime. Additionally, we show that the EMI shielding of the MXene-PAH long fiber composite laminates is highly dependent on the electron conduction path inside the fiber networks. This can provide a suitable strategy to design MXene-based EMI shields with tunable reflection and absorption of the incident EM waves.