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Ultralight Silver Nanowire Aerogel to Revolutionize Electronics

Le 17 octobre 2017, 12:02 dans Société 1

Researchers have developed new ultra-conductive and almost-weightless silver foam that could have many applications, from energy to hardware electronics.

Researchers are working to develop ultralight and low-density materials with interesting properties for thermal insulation, acoustic damping (soundproofing), vibration or shock isolation, battery electrodes, catalytic systems, and many other applications.

Recently, Russian researchers have developed new (aluminum-based) metal foam that could help make ships lighter and improve the function of bulkheads.

aerogel, a ‘foam’ created in multiple stages, is an ultra-light porous synthetic material derived from a metal gel where the liquid component is replaced by gas.

The result is solid with very low density and thermal conductivity that can be used in particular as a thermal insulation, a chemical absorber (in the event of a leak), an electrochemical supercapacitor, or a shock absorber.

Ultralight, Ultraconductive Silver Nanowire Aerogel

For a long time, production costs of aerogels prevented their entry to mass manufacture despite their very interesting properties.

Conventionally, metal foams are produced following complex processes that require high temperatures and high pressure or oxygen exclusion. These strict manufacturing conditions prevent scalability to mass production.

However, ongoing research is making significant progress in terms of scalability of aerogels’ production processes.

Researchers from the from Lawrence Livermore National Laboratory (LLNL) came up with a new industrially scalable method to produce silver nanowire aerogel.

LLNL researchers, whose main sponsor is the U.S. Department of Energy, started with silver nanowire as a building block which allowed them to overcome many of the limitations of other production methods.

The resulting aerogel is so ultralight and low-dense (4.8mg/cm3) that a delicate rosebud can hold it without sagging.

And with its excellent electrical and mechanical properties, this silver nanowire aerogel could find practical uses in several industries, such as energy storage, catalysis, fuel cells, medical devices, sensors, and other electronics.

“We are able to make these ultra-lightweight silver aerogels because the quality of our silver nanowires is extremely high,” said Professor Yong Han from LLNL and principal investigator of the project. “The custom feedstock synthesis capabilities we have at the Lab allow us to create such heat insulation material with demanding specifications for diverse application.”

The study describing LLNL’s new method was published in the online edition of Nano Letters, and the journal will also feature it on the cover of its December issue.



This Guy Holds These Super Hot Space Shuttle Tiles With His Bare Hands

Le 11 octobre 2017, 06:23 dans Société 1

Heat poses a massive problem to all things space related. Solving the problem of possible burning up on entry or reentry is no simple matter. But NASA did it and its results are shown in this awesome video captured during a tour of the Kennedy Space Centre.

NASA had to develop a totally new product to create the tiles that cover the Space Shuttle. The video shows this wall insulation materials being demonstrated in the most surprising way. Small blocks of the material are pulled out of a 2200°F (1204°C) oven and placed on a cooling rack for just seconds before the guide picks up the still burning cube with his bare hands. The crazy demo shows just how fast this material can shed heat. The material in question is LI-900.

LI-900 is a low-density surface insulation created almost entirely from silica glass. The material is almost pure quartz and is 94% air by volume. The tiles work because both air and silica glass are very poor conductors of heat.

As tiles on the space shuttle, the LI-900 protected the vehicle from heat as it made its reentry to earth. In an unusual detail the tiles weren’t fixed to the shuttle with mechanical fixings, rather they were glued in place to allow for easy replacement. A feature extremely necessary as many tiles were damaged after every space shuttle mission.