Category Physics

(a) Schematic cross-sectional diagram of the device. In the absence of an electric field, the surfaces are relatively smooth, and light passes through without being scattered or refracted. (b) When connected to a high-voltage source, the nanowires locally compress the elastomer, deforming its surface. Since the nanowires are randomly oriented, the resulting deformation diffuses light passing through the device. (c–f) Changes of opacity at the indicated actuation voltage from 0 to 2.2 kV, demonstrating control over the in-line transmittance using electrical potential. The logo and text are located 15 cm behind the circular film. The black rectangles are electrical contacts to the two sides of nanowire electrodes.

Method turns glass from clear to opaque with the flick of a switch...

Analysis of the possible shapes of the extruded cube unit cell.

Imagine a house that could fit in a backpack or a wall that could become a window with the flick of a switch. Harvard researchers have designed a new type of foldable material that is versatile, tunable and self actuated. It can change size, volume and shape; it can fold flat to withstand the weight of an elephant without breaking, and pop right back up to prepare for the next task.

“We’ve designed a three-dimensional, thin-walled structure that can be used to make foldable and reprogrammable objects of arbitrary architecture, whose shape, volume and stiffness can be dramatically altered and continuously tuned and controlled,” said Johannes T. B. Overvelde, graduate student in Bertoldi’s lab.

The structure is inspired by an or...

On your car windshield, ice is a nuisance. But on an airplane, a wind turbine, an oil rig or power line, it can be downright dangerous. And removing it with the methods that are available today – usually chemical melting agents or labor-intensive scrapers and hammers – is difficult and expensive work.

That could soon change thanks to a durable, inexpensive ice-repellent coating developed by University of Michigan researchers. Thin, clear and slightly rubbery to the touch, the spray-on formula could make ice slide off equipment, airplanes and car windshields with only the force of gravity or a gentle breeze. This could have major implications in industries like energy, shipping and transportation, where ice is a constant problem in cold climates.

The new coating could also lead to big ener...

Larry Lu (left), and Jiong Yang with the lens shown on screen. Credit: Image Stuart Hay, ANU

Scientists have created the world’s thinnest lens, 1/2000 the thickness of a human hair, opening the door to flexible computer displays and a revolution in miniature cameras. Dr Yuerui (Larry) Lu from The Australian National University (ANU) said the discovery hinged on the remarkable potential of the molybdenum disulphide crystal. “This type of material is the perfect candidate for future flexible displays,” said Dr Lu. “We will also be able to use arrays of micro lenses to mimic the compound eyes of insects.”

The 6.3-nanometre lens outshines previous ultra-thin flat lenses, made from 50-nanometre thick gold nano-bar arrays, known as a metamaterial.
“Molybdenum disulphide is an amazing crystal,” s...