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Polymer film protects against electromagnetic radiation and signal interference

3 Polymer film filled with nanowires. Credit: Zahra Barani / UC Riverside “width =” 800 “height =” 530 “/>

Polymer film filled with quasi 1DTaSe3 Nanowire. Credits: Zahra Barani / UC Riverside

As electronics saturate into every corner of public and personal life, engineers are able to protect humans from excessive electromagnetic radiation and prevent them from interfering with each other, being lightweight and mechanically stable. We are looking for materials that are flexible and easy to manufacture.


In a groundbreaking report published in Advanced materialEngineers at the University of California, Riverside are the leading journals in the field, describing flexible films using quasi-one-dimensional nanomaterial fillers that combine excellent electromagnetic shielding with ease of manufacture.

“These new films are promising for high-frequency communication technologies that require flexible, lightweight, corrosion-resistant, inexpensive, and electrically insulating electromagnetic interference shield films,” said Alexander, a prominent professor of electricity and computers. A. Balandin says. Engineering at the Marlan and Rosemary Bones Institute of Technology at the University of California, Riverside. “They are strongly coupled to high frequency and high frequency radiation while maintaining electrical insulation in DC measurements.”

Electromagnetic interference (EMI) occurs when signals from different electronic devices intersect each other and impacts performance. For example, the WiFi on your cell phone or laptop, or even the signal from your kitchen blender, can cause static electricity to appear on your TV screen. Similarly, airlines instruct passengers to turn off their mobile phones during landing and takeoff, as signals can interfere with navigation signals.

Engineers long ago learned that any electrical device could affect the functionality of nearby devices and developed materials to protect electronic devices from interference signals. But now that electronics are ubiquitous, small, wirelessly connected, and critical to a myriad of critical services, the chances and risks of EMI malfunctions are skyrocketing, and traditional EMI shielding materials are often inadequate. There is. More electronics mean that humans are also exposed to more electromagnetic radiation than before. Next-generation electronic devices will require new shielding materials.

Balandin led a team that developed a scalable synthesis of composites containing rare fillers. This is a bundle of chemically exfoliated quasi-one-dimensional van der Waals material. Composites have demonstrated excellent EMI shielding materials in the gigahertz and sub-terahertz frequency ranges that are important for current and future communication technologies while maintaining electrical insulation.

Graphene is the most famous van der Waals material. It is two-dimensional because it is a plane of strongly bonded atoms. Many faces of graphene that are weakly bound by van der Waals forces make up bulk graphite crystals. For many years, research has focused specifically on two-dimensional layered van der Waals materials that exfoliate into the plane of atoms.

ポリマーフィルムは、電磁放射、信号干渉から保護します

Quasi 1DTaSe3 Nanowire. Credits: Zahra Barani / UC Riverside

One-dimensional van der Waals materials are composed of strongly bonded atomic chains rather than planes that are weakly bonded by van der Waals forces. Such materials peel into a “one-dimensional” structure, such as a needle, rather than a two-dimensional plane. The Balandin group conducted pioneering research on one-dimensional metals and demonstrated their anomalous properties. In a new treatise, the Balandin Group reports that it uses scale-up chemical processes for the mass production of these one-dimensional materials.

Ph.D. students Zahra Barani and Fariboz Kargar, a research professor and project scientist at Phonon Optimized Engineered Materials (POEM Center) in Balandin, have synthesized their own composites by treating the transition metal tricalcogenide (TaSe).3, A layered van der Waals material with a quasi-one-dimensional crystal structure, using chemicals, needle-shaped quasi-1D van der Waals nanowires with very large aspect ratios (much longer than thickness) up to 106 Was released.In a previous study, the group had a quasi 1DTaSe bundle3 Atmix Red can support high current densities.

“There was no standard recipe for peeling these materials. We did a lot of trial and error experiments, checking for cleavage energy and other important parameters, and peeled in high yield. It turned out to be to get a bundle with a high aspect ratio. Whenever possible, the EM wave binds better with longer and thinner strands, so after each peeling step optical microscopy and scanning electrons. We needed to characterize the microscopy, “said lead author Barani.

Researchers filled a matrix made of a special polymer with a bundle of exfoliated TaSe.3 Create a thin black film. The synthetic composite film showed exceptional performance in blocking electromagnetic waves while maintaining electrical insulation. Polymer composites with low filler filling were particularly effective.

“The electromagnetic shielding effect of composites correlates with the aspect ratio of the filler. The higher the aspect ratio, the lower the filler concentration required to provide the critical EM shield,” says Kargar. .. “This is beneficial because it allows you to take advantage of polymer-specific properties such as light weight and flexibility by reducing the filler content. In this regard, this class of material is properly stripped and has thickness control. And the length. “

“In the end, I understood them correctly, prepared the composites and measured the EMI properties. The results were amazing. There is no conductivity, but the EMI shield of the micrometer thick film is 99.99. That’s over%, “Barani added.

Semi-1D van der Waals metal fillers are inexpensive and can be manufactured in large quantities. Balandin said research on atomic bundles of quasi-1D van der Waals materials as individual conductors, and composites with such materials, has just begun.

“I’m confident that we’ll see a lot of progress soon with quasi-1D van der Waals materials, just as we did with quasi-2D materials,” he said.


Researchers are using MXene to develop nanometer-thick electromagnetic shield films


For more information:
Zahra Barani et al, Electrically insulated flexible film with quasi 1D van der Waals filler as an efficient electromagnetic shield in the GHz and sub-THz frequency bands, Advanced material (2021). DOI: 10.1002 / adma.202007286

Courtesy of the University of California, Riverside

Quote: Polymer film protects from electromagnetic radiation, signal interference (2021, 22 February) obtained from https://phys.org/news/2021-02-polymer-electromagnetic.html on 22 February 2021 Was

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Polymer film protects against electromagnetic radiation and signal interference

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