Habibpour Saeed, Rahimi-Darestani Yasaman, Salari Meysam, Zarshenas Kiyoumars, Taromsari Sara Mohseni, Tan Zhongchao, Hamidinejad Mahdi, Park Chul B, Yu Aiping
Department of Chemical Engineering, Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue West, Waterloo, N2L 3G1, Canada.
Microcellular Plastics Manufacturing Laboratory, Department of Mechanical and Industrial Engineering, University of Toronto, 5 King's College Road, Toronto, M5S 3G8, Canada.
Small. 2024 Nov;20(45):e2404876. doi: 10.1002/smll.202404876. Epub 2024 Jul 27.
Electromagnetic pollution presents growing challenges due to the rapid expansion of portable electronic and communication systems, necessitating lightweight materials with superior shielding capabilities. While prior studies focused on enhancing electromagnetic interference (EMI) shielding effectiveness (SE), less attention is given to absorption-dominant shielding mechanisms, which mitigate secondary pollution. By leveraging material science and engineering design, a layered structure is developed comprising rGOnR/MXene-PDMS nanocomposite and a MXene film, demonstrating exceptional EMI shielding and ultra-high electromagnetic wave absorption. The 3D interconnected network of the nanocomposite, with lower conductivity (10-10 S/cm), facilitates a tuned impedance matching layer with effective dielectric permittivity, and high attenuation capability through conduction loss, polarization loss at heterogeneous interfaces, and multiple scattering and reflections. Additionally, the higher conductivity MXene layer exhibits superior SE, reflecting passed electromagnetic waves back to the nanocomposite for further attenuation due to a π/2 phase shift between incident and back-surface reflected electromagnetic waves. The synergistic effect of the layered structures markedly enhances total SE to 54.1 dB over the K-band at a 2.5 mm thickness. Furthermore, the study investigates the impact of hybridized layered structure on reducing the minimum required thickness to achieve a peak absorption (A) power of 0.88 at a 2.5 mm thickness.
由于便携式电子和通信系统的迅速扩张,电磁污染带来了日益严峻的挑战,因此需要具有卓越屏蔽能力的轻质材料。虽然先前的研究侧重于提高电磁干扰(EMI)屏蔽效能(SE),但对以吸收为主的屏蔽机制关注较少,而这种机制可减轻二次污染。通过利用材料科学和工程设计,开发出一种由rGOnR/MXene-PDMS纳米复合材料和MXene薄膜组成的分层结构,该结构展现出优异的EMI屏蔽和超高的电磁波吸收能力。纳米复合材料的三维互连网络具有较低的电导率(10-10 S/cm),有助于形成具有有效介电常数的调谐阻抗匹配层,并通过传导损耗、异质界面处的极化损耗以及多次散射和反射实现高衰减能力。此外,具有较高电导率的MXene层表现出卓越的SE,由于入射电磁波和背表面反射电磁波之间存在π/2的相位差,它将透过的电磁波反射回纳米复合材料进行进一步衰减。分层结构的协同效应在2.5毫米厚度下将K波段的总SE显著提高到54.1分贝。此外,该研究还探讨了混合分层结构对降低达到2.5毫米厚度时0.88的峰值吸收(A)功率所需最小厚度的影响。