ADVANCED MATERIALS & PROCESSES | MARCH 2024 1 1 NANOTUBES HELP HELMETS TOUGHEN UP A new material developed by University of Wisconsin-Madison engineers could mitigate or even prevent traumatic brain injuries when used as helmet lining. The material—a vertically aligned carbon nanotube foam— weakens rotational kinetic energy before it reaches the brain. In fact, the material is 30 times better at absorbing energy in shear than the foam currently used in U.S. military combat helmet liners. At present, some helmets attempt to reduce rotational motion from impacts by employing a layer that allows a sliding motion to occur between the wearer’s head and the helmet’s outer shell. However, these moving layers don’t dissipate energy in shear and tend to jam when severely compressed. Since the new material doesn’t rely on sliding layers, it sidesteps these shortcomings. Furthermore, when it’s compressed, the material gets unusually better at accommodating shear and dissipating energy from an impact, according to the researchers. The new foam consists of carbon nanotubes that are carefully arranged into closely packed cylindrical structures. The material’s novel architecture, which has unique structural features across multiple length scales, gives the material its exceptional properties. In addition, the researchers recently demonstrated that their foams exhibited outstanding thermal conductivity and diffusivity, which would enable a helmet liner made of the material to keep the wearer’s head cool in hot environments. Coupled with its thinness, that cooling capability puts the new material on par with graphite foams and makes it attractive for applications where less weight is important. Beyond helmet liners, the material could also be used in electronic packaging and electronic systems to both protect against shocks and keep electronics cool. wisc.edu. MAKING MATERIALS FROM MARS WASTE Using resources and techniques currently applied on the International Space Station and by NASA, a research group at the University of Sussex, U.K., is investigating the potential of nanomaterials for clean energy production and building materials on Mars. Taking what was considered a NANOTECHNOLOGY Bhanugoban Maheswaran tests the vertically aligned carbon nanotube foams in Assistant Professor Ramathasan Thevamaran’s lab. Courtesy of Joel Hallberg. waste product by NASA and applying only sustainable production methods, including water-based chemistry and low-energy processes, the researchers have successfully identified electrical properties within gypsum nano-materials. Resulting materials could have a range of applications from creating clean hydrogen fuel to developing an electronic device similar to a transistor, to creating an additive to textiles to increase their robustness. The researchers say their findings open avenues for sustainable technology—and building—on Mars but also highlight the broader potential for eco-friendly breakthroughs here on Earth. To make the discovery, the researchers used NASA’s innovative method for extracting water from Martian gypsum, which is dehydrated by the agency to get water for human consumption. This produces a byproduct called anhydrite, considered waste material by NASA, but now shown to be hugely valuable. The Sussex researchers processed anhydrite into nanobelts—essentially tagliatelleshaped materials—demonstrating their potential to provide clean energy and sustainable electronics. Furthermore, at every step of their process, water could be continuously collected and recycled. The group is optimistic about the process’ feasibility on Mars, as it requires only naturally occurring materials. www.sussex.ac.uk. Researchers at Rice University, Houston, developed new methods to create synthetic chiral carbon nanotube assemblies, enhancing control over the properties of polarized light. The team says these discoveries could revolutionize applications in optoelectronics, quantum computing, and other industries. rice.edu. BRIEF From le : Two types of Martian rock, a vial of nanobelts in water, and a close up of nanobelts. Courtesy of University of Sussex.
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