Super-Tough and Environmentally Stable Aramid Nanofiber@MXene Coaxial Fibers with Outstanding Electromagnetic Interference Shielding Efficiency

Although electrically conductive and hydrophilic MXene sheets are promising for multifunctional fibers and electronic textiles,it is still a challenge to simultaneously enhance both conductivity and mechanical properties of MXene fibers because of the high rigidity of MXene sheets and insufficient inter-sheet interactions.Herein,we demonstrate a core-shell wet-spinning methodology for fabricating highly conductive,super-tough,ultra-strong,and environmentally stable Ti_(3)C_(2)T_(x) MXene-based core-shell fibers with conductive MXene cores and tough aramid nanofiber(ANF)shells.The highly orientated and low-defect structure endows the ANF@MXene core-shell fiber with supertoughness of~48.1 MJ m^(-3),high strength of~502.9 MPa,and high conductivity of~3.0×10^(5)S m^(-1).The super-tough and conductive ANF@MXene fibers can be woven into textiles,exhibiting an excellent electromagnetic interference(EMI)shielding efficiency of 83.4 dB at a small thickness of 213μm.Importantly,the protection of the ANF shells provides the fibers with satisfactory cyclic stability under dynamic stretching and bending,and excellent resistance to acid,alkali,seawater,cryogenic and high temperatures,and fire.The oxidation resistance of the fibers is demonstrated by their wellmaintained EMI shielding performances.The multifunctional core-shell fibers would be highly promising in the fields of EMI shielding textiles,wearable electronics and aerospace.

Direct ink writing of multifunctional gratings with gel-like MXene/norepinephrine ink for dynamic electromagnetic interference shielding and patterned Joule heating

Intelligent electromagnetic interference(EMI)shielding modulators with a wide tuning range and cyclic stability are urgently needed but their fabrication remains challenging.A gel-like MXene/norepinephrine ink is developed and multifunctional MXene gratings with wide EMI shielding effectiveness(SE)tuning range,superior reversibility,and high mechanical flexibility are constructed by direct ink writing approach for dynamic EMI shielding and patterned Joule heating applications.The modulable MXene/norepinephrine grating with a high conductivity of 3510 S·cm-1 can conveniently realize the seamless modulation of the EMI SE by adjusting the angle between the MXene grating filaments and the electric field of the incident electromagnetic waves,offering highly reversible switching between shielding“On”(28.0 dB)and“Off”(0.5 dB)states.Notably,due to the optimized integration of the MXene ink and the rationally designed pattern,a superior specific EMI SE of 95,688.2 dB·cm^(2)·g^(-1) is achieved in the“On”state.Furthermore,the MXene/norepinephrine ink can be used to fabricate many complex patterned gratings with superior stability,instant responsibility,and superb mechanical flexibility,exhibiting a unique patterned Joule heating behavior.Direct writing of multifunctional gratings paves a means for developing intelligent EMI shielding materials,wearable electronic devices,and advanced thermal management materials.