Researchers at North Carolina State University have developed a technique that uses light to get two-dimensional (2-D) plastic sheets to curve into three-dimensional (3-D) structures, such as spheres, tubes or bowls.
The advance builds on earlier work by the same research team, which focused on self-folding 3-D structures. The key advance here is that rather than having the plastic fold along sharp lines -- into polygonal shapes such as cubes or pyramids -- the plastics bend and curve.
Researchers Michael Dickey, a professor of chemical and biomolecular engineering at NC State, and Jan Genzer, the S. Frank and Doris Culberson Distinguished Professor in the same department, were early leaders in the field of self-folding 3-D structures. In their landmark 2011 paper, the researchers outlined a technique in which a conventional inkjet printer is used to print bold black lines onto a pre-strained plastic... more
Yale scientists have developed an ultra-thin coating material that has the potential to extend the life and improve the efficiency of lithium-sulfur batteries, one of the most promising areas of energy research today.
In a study published online March 20 in the Proceedings of the National Academy of Sciences, researchers describe the new material -- a dendrimer-graphene oxide composite film -- which can be applied to any sulfur cathode. A cathode is the positive terminal on a battery.
According to the researchers, sulfur cathodes coated with the material can be stably discharged and recharged for more than 1,000 cycles, enhancing the battery's efficiency and number of cycles.
"Our approach is general in that it can be integrated with virtually any kind of sulfur electrode to increase cycling stability," said Hailiang Wang, assistant professor of chemistry at Yale and lead investigator... more
Researchers at Rice University and the Indian Institute of Science have an idea to simplify electronic waste recycling: Crush it into nanodust.
Specifically, they want to make the particles so small that separating different components is relatively simple compared with processes used to recycle electronic junk now.
Chandra Sekhar Tiwary, a postdoctoral researcher at Rice and a researcher at the Indian Institute of Science in Bangalore, uses a low-temperature cryo-mill to pulverize electronic waste - primarily the chips, other electronic components and polymers that make up printed circuit boards (PCBs) -- into particles so small that they do not contaminate each other.
Then they can be sorted and reused, he said.
The process is the subject of a Materials Today paper by Tiwary, Rice materials scientist Pulickel Ajayan and Indian... more
Physicists have simulated the structure of a new material based on fullerite and single crystal diamond to show how this material can obtain ultrahigh hardness.
This discovery allows the estimations the potential conditions for obtaining ultrahard materials. The results were published in the Carbon journal.
Fullerite generally is a molecular crystal with fullerene molecules at its lattice nodes. Fullerenes are a form of molecular carbon where carbon atoms form a sphere. It was first synthesized over thirty years ago, and its discovery was awarded with the Nobel Prize. Carbon spheres in fullerite may be packed in different ways, and the hardness of the material strongly depends on how the fullerenes are connected to each other. A group of scientists from the Moscow Institute of Physics and Technology (MIPT), the Skolkovo Institute of Science and... more
University of Utah engineers develop non-toxic material that generates electricity through hot and cold.
Thanks to the discovery of a new material by University of Utah engineers, jewelry such as a ring and your body heat could generate enough electricity to power a body sensor, or a cooking pan could charge a cellphone in just a few hours.
The team, led by University of Utah materials science and engineering professor Ashutosh Tiwari, has found that a combination of the chemical elements calcium, cobalt and terbium can create an efficient, inexpensive and bio-friendly material that can generate electricity through a thermoelectric process involving heat and cold air.
Their findings were published in a new paper March 20 in the latest issue of Scientific Reports. The first author on the paper... more
Consumers want fuel-efficient vehicles and high-performance sporting goods, municipalities want weather-resistant bridges, and manufacturers want more efficient ways to make reliable cars and aircraft.
What's needed are new lightweight, energy-saving composites that won't crack or break even after prolonged exposure to environmental or structural stress. To help make that possible, researchers working at the National Institute of Standards and Technology (NIST) have developed a way to embed a nanoscale damage-sensing probe into a lightweight composite made of epoxy and silk.
The probe, known as a mechanophore, could speed up product testing and potentially reduce the amount of time and materials needed for the development of many kinds of new composites.
The NIST team created their probe from a dye known as rhodamine spirolactam (RS), which changes from a dark state to a light... more
Aalto University / University of Uppsala / EPFL
Researchers lengthened the lifetime of perovskite solar cells by using nanotube film to replace the gold used as the back contact and the organic material in the hole conductor.
Five years ago, the world started to talk about third-generation solar cells that challenged the traditional silicon cells with a cheaper and simpler manufacturing process that used less energy.
Methylammonium lead iodide is a metal-organic material in the perovskite crystal structure that captures light efficiently and conducts electricity well -- both important qualities in solar cells. However, the lifetime of solar cells made of metalorganic perovskites has proven to be very short compared to cells made of silicon.
Now researchers from Aalto University, Uppsala University and École polytechnique fédérale de Lausanne (EPFL) in Switzerland have managed to improve the long term stability... more
Picture a tablet that you can fold into the size of a phone and put away in your pocket, or an artificial skin that can sense your body's movements and vital signs.
A new, inexpensive sensor developed at the University of British Columbia could help make advanced devices like these a reality.
The sensor uses a highly conductive gel sandwiched between layers of silicone that can detect different types of touch, including swiping and tapping, even when it is stretched, folded or bent. This feature makes it suited for foldable devices of the future.
"There are sensors that can detect pressure, such as the iPhone's 3D Touch, and some that can detect a hovering finger, like Samsung's AirView. There are also sensors that are foldable, transparent and stretchable. Our contribution is a device that combines all those functions in one compact... more
New research offers insights into how crystal dislocations -- a common type of defect in materials -- can affect electrical and heat transport through crystals, at a microscopic, quantum mechanical level.
Dislocations in crystals are places where the orderly three-dimensional structure of a crystal lattice -- whose arrangement of atoms repeats with exactly the same spacing -- is disrupted. The effect is as if a knife had sliced through the crystal and then the pieces were stuck back together, askew from their original positions. These defects have a strong effect on phonons, the modes of lattice vibration that play a role in the thermal and electrical properties of the crystals through which they travel. But a precise understanding of the mechanism of the dislocation-phonon interaction has been elusive and controversial, which has slowed progress toward using dislocations to tailor the thermal... more
Iron nanocubes may be key in the future of NO2 sensing
While nanoparticles sound like a recent discovery, these tiny structures have been used for centuries. The famous Lycurgus cup, made by 4th century Roman artisans, features dichroic glass, with gold and silver nanoparticles sprinkled throughout, producing a green appearance when light is shining on it from the front, and a red appearance when illuminated from behind.
In the centuries since the time of the ancient artisans, researchers have come a long way in understanding nanoparticles. The production of nanocubes has been of particular interest due to their potential applications as biosensors and gas sensors. Nanoparticles can be produced using either physical or chemical methods, though... more