The internet of things. The whole world connected together so we can adjust our home thermostat or turn the lights off while scaling Kilimanjaro. Refrigerators that call for a service technician before the compressor fails. EV chargers that talk to utility companies to take advantage of pricing signals so we can help balance the grid and save money on electricity. Wearable heart monitors that warn of life threatening conditions before they occur. Kyle did a wonderful story the other day about the new sonnen ecoLinx home energy storage system that employs many IoT components.
The number of IoT permutations is virtually endless. At some point in the future, billions of devices could be connected to the internet, saving lives, time, and money. Only one thing has been holding the technology back — the need to have some sort of physical antenna to permit the connection between devices and servers. Until now, that is.
Researchers at the Drexel College of Engineering say they have developed a flexible antenna that works as well as a traditional antenna but can be sprayed on as easily as bug spray. Their report, published September 21 in Science Advances, reveals that ultra-thin antennas (antennae for those of you who took Latin in high school) made from two dimensional MXene perform as well as the conventional antennas used in today’s mobile devices, wireless routers, and portable transducers.
“This is a very exciting finding because there is a lot of potential for this type of technology,” says professor Kapil Dandekar, who directs the Drexel Wireless Systems Lab, and is a co-author of the report. “The ability to spray an antenna on a flexible substrate or make it optically transparent means that we could have a lot of new places to set up networks — there are new applications and new ways of collecting data that we can’t even imagine at the moment.”
“This technology could enable the truly seamless integration of antennas with everyday objects which will be critical for the emerging Internet of Things,” Dandekar says. “Researchers have done a lot of work with non-traditional materials trying to figure out where manufacturing technology meets system needs, but this technology could make it a lot easier to answer some of the difficult questions we’ve been working on for years.”
MXene titanium carbide can be dissolved in water to create an ink or paint. The exceptional conductivity of the material enables it to transmit and direct radio waves, even when it’s applied in a very thin coating. “We found that even transparent antennas with thicknesses of tens of nanometers were able to communicate efficiently,” says doctoral candidate Asia Sarycheva. “By increasing the thickness up to 8 microns, the performance of MXene antenna achieved 98 percent of its predicted maximum value.”
Test show the spray-on antennas work as well as those made from gold, silver, copper, or aluminum — all of which are much thicker and less flexible than the MXene items, making them ideal for a broad range of new applications.
“Current fabrication methods of metals cannot make antennas thin enough and applicable to any surface, in spite of decades of research and development to improve the performance of metal antennas,” says Yury Gogotsi, director of the A.J. Drexel Nanomaterials Institute, who initiated and led the project. “We were looking for two dimensional nanomaterials which have sheet thickness about hundred thousand times thinner than a human hair — just a few atoms across — and can self-assemble into conductive films upon deposition on any surface. Therefore, we selected MXene, which is a two-dimensional titanium carbide material that is stronger than metals and is metallically conductive.”
Drexel researchers have been pioneers in the use of MXene, which has shown potential in energy storage devices, electromagnetic shielding, water filtration, chemical sensing, structural reinforcement, and gas separation. In 2017, they created electrodes for lithium ion batteries made from MXene that permit far more rapid charging than traditional electrodes.
“The MXene antenna not only outperformed the macro and micro world of metal antennas, we went beyond the performance of available nanomaterial antennas, while keeping the antenna thickness very low,” said Babak Anasori, a research assistant professor involved in the project.”The thinnest antenna was as thin as 62 nanometers — about a thousand times thinner than a sheet of paper — and it was almost transparent. Unlike other nanomaterials fabrication methods, that requires additives, called binders, and extra steps of heating to sinter the nanoparticles together, we made antennas in a single step by airbrush spraying our water-based MXene ink.”
The next step in the research will be finding ways to apply the spray-on antennas to a wide variety of surfaces from glass, yarn, and even human skin. “Further research on using materials from the MXene family in wireless communication may enable fully transparent electronics and greatly improved wearable devices that will support the active lifestyles we are living,” Anasori says.
Note to Donald Trump and his supporters: Every one of these researchers is either an immigrant or the child of immigrants. Some of them may come from so-called “shithole countries.” All of them are subject to harassment by authorities for the simple act of daring to appear in public. Thanks for making America hate again.
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