Computational Optimizing the Electromagnetic Wave Reflectivity of Double‐Layered Polymer Nanocomposites

Abstract

its effect on electronic elements may result in catastrophic failure of the whole system. [1][2][3][4] Moreover, people also focus on the harm to human health caused by the thermal effect of electromagnetic (EM) waves. [5][6][7][8][9] Therefore, the market demand for EMI shielding materials has undergone rapid growth in recent years. [10][11][12][13][14] There are two types of EM wave shielding, namely reflection and absorption. [15][16][17][18] Reflection-dominated EMI shielding material usually has high electrical conductivity and inferior impedance match. It blocks EM waves by reflecting them into the outer space, [19][20][21] thus generating unavoidable secondary EM wave pollution. [12,22,23] It is of great significance to develop absorption-dominated EMI shielding materials to prevent humans and devices from the secondary pollution of EM waves. [24][25][26] Absorption-dominated EMI shielding materials dissipate EM energy by converting it into thermal energy. [27] Allowing the EM waves to enter the material interior is an essential prerequisite to attenuate the EM energy. [28,29] Therefore, the simultaneous achievement of good impedance match and excellent shielding capacity is the critical requirement for absorption-dominated EMI shielding materials. Numerous research works [30][31][32] concentrate on structural design to improve the impedance match and shielding capacity. It usually consists of porous and Double-layered absorption-dominated electromagnetic interference (EMI) shielding composites are highly desirable to prevent secondary electromagnetic wave pollution. However, it is a tremendous challenge to optimize the shielding performance via the trial-and-error method due to the low efficiency. Herein, a novel approach of computation-aided experimental design is proposed to efficiently optimize the reflectivity of the double-layered composites. A normalized input impedance (NII) method is presented to calculate the electromagnetic wave reflectivity of multilayered EMI shielding composites. The calculated results are a good match with the experimental results. Then, the NII method is utilized to design polyvinylidene difluoride/MXene/carbon nanotube (PVDF/MXene/CNT) composites. According to the optimization of the NII method, the prepared PVDF/MXene/CNT composite has an ultralow reflectivity of 0.000057, which outperforms that reported in current work and satisfies the requirement of electromagnetic wave absorbing material. Additionally, its average EMI shielding effectiveness is 30 dB, demonstrating that PVDF/MXene/ CNT composite simultaneously achieves shielding and absorption. The ultralow reflection mechanism can be ascribed to the ideal impedance match. Both the PVDF/MXene and the PVDF/CNT layers can attenuate electromagnetic energy, which subverts the traditional cognition of double-layered absorption-dominated EMI shielding composites. The NII method opens a way for the practical fabrication of double-layered absorption-dominated EMI shielding composites.The ORCID identification number(s) for the...

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“…Furthermore, the layered MS structure in the composite films may result in effective multiple reflections of incident waves, improving SE A . Therefore, the high SE T value was mainly dominated by the SE A , which was similar to that of other nanofiller-embedded CPCs ever reported . The transmission (T), absorption (A), and reflection (R) power coefficients are displayed in Figure f to further shed light on the EMI shielding process.…”

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