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·cm²·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.