Water (and other liquids) has an unusual property when it flows closely to some specially designed surfaces: its speed isn't equal to zero even in the layer that directly touches the wall.
This means that liquid doesn't adhere to the surface, but instead slides along it. Such an effect is called hydrodynamic slip and it was first described more than 200 years ago. However, at that time it hasn't received much attention as it didn't significantly influence the cumulative liquid flow.
But the situation has totally changed after superhydrophobic materials were invented, where chemical hydrophobicity met a peculiar geometry of the surface (for instance, grooves or micro-pillars). In such texture's cavities there might be air bubbles trapped, which help the liquid to slip along the surface with almost no resistance, which has greatly increased the slip length... more
University of Alabama at Birmingham researchers will use pressures greater than those found at the center of the Earth to potentially create as yet unknown new materials.
In the natural world, such immense forces deep underground can turn carbon into diamonds, or volcanic ash into slate.
The ability to produce these pressures depends on tiny nanocrystalline-diamond anvils built in a UAB clean room manufacturing facility. Each anvil head is just half the width of an average human hair. The limits of their pressure have not yet been reached as the first 27 prototypes are being tested.
"We have achieved 75 percent of the pressure found at the center of the Earth, or 264 gigapascals, using lab-grown nanocrystalline-diamond micro-anvil," said Yogesh Vohra, Ph.D., a professor and university scholar of physics in the UAB College of Arts and Sciences... more
Medicine, mobile phones, computers and clothes could all be enhanced using the process for making paint, according to research by the University of Warwick.
A breakthrough in the understanding of polymers - the molecules from which almost everything we use is made - is set to make commercial products, from water bottles to electrical goods, stronger and more effective for their uses.
Professor David Haddleton from Warwick's Department of Chemistry has discovered a way to translate the specific requirements of a product into its essential molecular structure.
Enacting the same process from which we get emulsion paint and glue, complex polymers can be tailor-made, with producers able to write into the code - essentially, the DNA - of a molecule the exact properties needed for the final product (weight, strength, shape, size etc.)
Researchers from MIT and Harvard Medical School have developed a biocompatible and highly stretchable optical fiber made from hydrogel -- an elastic, rubbery material composed mostly of water.
The fiber, which is as bendable as a rope of licorice, may one day be implanted in the body to deliver therapeutic pulses of light or light up at the first sign of disease.
The researchers say the fiber may serve as a long-lasting implant that would bend and twist with the body without breaking down. The team has published its results online in the journal Advanced Materials.
Using light to activate cells, and particularly neurons in the brain, is a highly active field known as optogenetics, in which researchers deliver short pulses of light to targeted tissues using needle-like fibers, through which they shine light from an LED source.
"But the brain is like a bowl of Jell-O, whereas... more
Berkeley Lab and University of Colorado-Boulder team develop new way to reveal crystal features in functional materials
Detailing the molecular makeup of materials -- from solar cells to organic light-emitting diodes (LEDs) and transistors, and medically important proteins -- is not always a crystal-clear process.
To understand how materials work at these microscopic scales, and to better design materials to improve their function, it is necessary to not only know all about their composition but also their molecular arrangement and microscopic imperfections.
Now, a team of researchers working at the Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) has demonstrated infrared imaging of an organic semiconductor known for its electronics capabilities, revealing key nanoscale... more
Method for moving fluids on a surface may find uses in condensers, microfluidics, and de-icing.
Researchers at MIT and elsewhere have developed a new way of driving fluid droplets across surfaces in a precisely controlled way. The method could open up new possibilities for highly adaptable microfluidic devices, as well as for de-icing technologies, self-cleaning surfaces, and highly efficient condensers.
The new system uses differences in temperature to push droplets of water or other fluids across a smooth surface, allowing precise control by simply turning heaters and coolers on and off. The finding is described this week in the journal Physical Review Fluids, in a paper by MIT associate professor of mechanical engineering Kripa Varanasi, professor David Quere at ESPCI in Paris... more
Less than a micrometre thin, bendable and giving all the colours that a regular LED display does, it still needs ten times less energy than a Kindle tablet.
Researchers at Chalmers University of Technology have developed the basis for a new electronic "paper". Their results were recently published in the high impact journal Advanced Materials.
When Chalmers researcher Andreas Dahlin and his PhD student Kunli Xiong were working on placing conductive polymers on nanostructures, they discovered that the combination would be perfectly suited to creating electronic displays as thin as paper. A year later the results were ready for publication. A material that is less than a micrometre thin, flexible and giving all the colours that a standard LED display does.
"The 'paper' is similar to the Kindle tablet", says Andreas... more
In 2014, when University of Wisconsin-Madison engineers announced in the journal Nature Communications that they had developed transparent sensors for use in imaging the brain, researchers around the world took notice.
Then the requests came flooding in. "So many research groups started asking us for these devices that we couldn't keep up," says Zhenqiang (Jack) Ma, the Lynn H. Matthias Professor and Vilas Distinguished Achievement Professor in electrical and computer engineering at UW-Madison.
Ma's group is a world leader in developing revolutionary flexible electronic devices. The see-through, implantable micro-electrode arrays were light years beyond anything ever created.
Although he and collaborator Justin Williams, the Vilas Distinguished Achievement Professor in biomedical engineering and neurological surgery at UW-Madison, patented the technology through the Wisconsin Alumni... more
Robots are usually expected to be rigid, fast and efficient. But researchers at EPFL's Reconfigurable Robotics Lab (RRL) have turned that notion on its head with their soft robots.
Soft robots, powered by muscle-like actuators, are designed to be used on the human body in order to help people move. They are made of elastomers, including silicon and rubber, and so they are inherently safe. They are controlled by changing the air pressure in specially designed 'soft balloons', which also serve as the robot's body. A predictive model that can be used to carefully control the mechanical behavior of the robots' various modules has just been published in Scientific Reports.
Potential applications for these robots include patient rehabilitation, handling fragile objects, biomimetic systems and home care. "Our robot designs focus largely on safety... more
Researchers at Georgia Institute of Technology have developed a new process for treating metal surfaces that has the potential to improve efficiency in piston engines and a range of other equipment.
The method improves the ability of metal surfaces to bond with oil, significantly reducing friction without special oil additives.
"About 50 percent of the mechanical energy losses in an internal combustion engine result from piston assembly friction. So if we can reduce the friction, we can save energy and reduce fuel and oil consumption," said Michael Varenberg, an assistant professor in Georgia Tech's George W. Woodruff School of Mechanical Engineering.
In the study, which was published Oct. 5 in the journal Tribology Letters, the researchers at Georgia Tech and Technion - Israel Institute of Technology tested treating the surface of cast iron blocks by blasting it with... more