Shield against polluting radiation
doi:10.1038/nindia.2011.161 Published online 7 November 2011
Researchers have produced a new nanocomposite based on graphene oxide that is capable of absorbing electromagnetic radiation. This nanocomposite will be useful for designing shields against electromagnetic pollution.
Electromagnetic radiation such as radio waves tends to interfere with electronic devices. The ideal material for protecting against such interference is one that neither reflects nor transmits an electromagnetic wave. Metallic enclosures and metallic fillers reflect electromagnetic waves. In contrast, shields made from plastic are transparent to electromagnetic radiation.
To devise a better shielding material, the researchers produced a nanocomposite from graphene oxide nanosheets — a ferrofluid containing ferric oxide nanoparticles and cement. To study the shielding effectiveness of the nanocomposite, they carried out experiments that involved exposing the nanocomposite to electromagnetic radiation.
The researchers observed that the shielding effectiveness of the nanocomposite was mainly dominated by absorption, while the shielding effectiveness due to reflection was nominal and contributed very little. They also found that an increase in ferrofluid in the cement matrix of the nanocomposite enhanced the permeability of the nanocomposite, leading to a higher shielding effectiveness. The study demonstrates that the nanocomposite could be used as a shielding material against electromagnetic radiation from radio waves to microwaves.
"The nanocomposite could be coated as a formulation on an enclosure in which electronic devices are kept," says lead researcher S. K. Dhawan. The nanocomposite can also be blended with conventional polymers used to develop enclosures for electronic devices, he adds.
The authors of this work are from: Polymeric and Soft Materials Section, CSIR—National Physical Laboratory, and Department of Physics and Astrophysics, University of Delhi, Delhi, India.