Electromagnetic Shields Based on MXene Nano-Metamaterials

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All modern electronics uses electromagnetic shields to cut down on electrical interferences that can completely destroy information stored and passed by the electronic components. This is particularly important in military applications, medical electronics and consumer wireless systems including wearable devices and 5G cell phones. The present day electromagnetic shielding technology is challenged to keep up with the need for being lighter and smaller. Conventional metal shields commonly used today are bulky and lack mechanical flexibility. The proposed work focuses on developing new highly effective electromagnetic shields of dramatically reduced weight and size. They will be thinner than sheets of paper and completely flexible. This new technology is based on the recently discovered new class of materials called MXenes. The proposal will develop MXene electromagnetic shields that can be laid over flexible electronics and even spray painted over it. We will learn how to optimize shielding behavior of these novel materials and develop software and models to help creators of modern electronics to design the most effective electromagnetic shields.While previous work demonstrated that MXene layers thinner than typical copper shields are capable of shielding electromagnetic fields in the RF and microwave region just as well, there has been no clear explanation for the reasons behind such outstanding performance. Yet, understanding is critical to developing thinner, lighter and more flexible shielding devices. Preliminary measurements indicate that MXene, despite having conductivity lower than copper, has an anomalously high effective dielectric constant. This seems to result in the material characteristic impedance low enough to explain MXene’s great shielding performance. It is known that high dielectric constant can be obtained in artificially created conducting structures known as meta-materials. We conjecture that MXene has certain micro-structural features that, although somewhat random, result in meta-material-like behavior. To develop a much better understanding of this behavior and to design more effective shields, the proposed work will combine analytical and numerical electromagnetic modeling and simulations with fabrication of MXene shielding devices and their experimental testing. Modeling and simulation work will focus on quasi-periodic micro-structure of MXenes in order to determine the circumstances under which these materials would have high effective dielectric constant combined with high effective conductivity. Candidate MXene structures most likely to yield best shields will be fabricated into sheets and filler epoxy-based shields and tested using waveguides and near-field measurements. Modeling and simulation results will be compared with the experimental measurements for model validation.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.