Magnetic field-induced strategy for synergistic CI/Ti3C2T /PVDF multilayer structured composite films with excellent electromagnetic interference shielding performance

Lightweight, scalable, mechanically flexible conductive polymer composite was always desirable for electromagnetic interference (EMI) shielding applications. In this work, we showcased a novel approach to the superior EMI shielding composite materials by orchestrating the multilayered structure and synergistic system. The asymmetric structure with the carbonyl irons (CI)-rich Ti3C2Tx/poly(vinylidene fluoride) (PVDF) magneto-electric layer jointly behind the Ti3C2Tx nanosheets filled PVDF layer was designed and fabricated with the aid of a facile but efficient magnetic field-induced method and was then hot-pressed into a multilayer structured film. Ti3C2Tx nanosheets were excluded by CI agglomeration layer in the asymmetric film to form the complete 3D electrical conductive skeletons. Based on this strategy, EMI shielding properties of the asymmetric multilayer structured composite was superior to the homogeneous blend and sandwiched or alternating layered composites. In addition, an increase in CI content in the composite referred to the thickening of CI-rich layers, making it gain the most powerful EMI SE values, i.e. 42.8 dB for DCMP20–10 film (20 wt% CI, 10 wt% Ti3C2Tx) at a thickness of 0.4 mm. More importantly, the composite transformed from a reflection type to an absorption dominating EMI shielding material due to the multireflections and magneto-electric synergism in the CI-rich Ti3C2Tx/PVDF layers. Meanwhile, the EMI SE of the composites can be adjusted by increase of either theoverall thickness, or the layer numbers of m-DCMP sheets. The thickness specific EMI SE was calculated as 165.25 dB mm−1 for 4-sheet composite film, a record high value among the high efficiency polymer-based EMI shielding materials. This method offered an alternative protocol for preferential integration of excellent EMI shielding performance with high mechanical performance in CPC materials.