. 24/7 Space News .
TECH SPACE
A new form of real gold, almost as light as air
by Staff Writers
Zurich, Switzerland (SPX) Dec 03, 2015


Even when it seems unbelievable: these are genuine photographs, in which nothing has been faked. E.g. the 20 carats gold foam is lighter than milk foam. Image courtesy Gustav Nystrom and Raffaele Mezzenga / ETH Zurich. For a larger version of this image please go here.

A nugget of real 20 carats gold, so light that it does not sink in a cappuccino, floating instead on the milk foam - what sounds unbelievable has actually been accomplished by researchers from ETH Zurich. Scientists led by Raffaele Mezzenga, Professor of Food and Soft Materials, have produced a new kind of foam out of gold, a three-dimensional mesh of gold that consists mostly of pores.

It is the lightest gold nugget ever created. "The so-called aerogel is a thousand times lighter than conventional gold alloys. It is lighter than water and almost as light as air," says Mezzenga.

The new gold form can hardly be differentiated from conventional gold with the naked eye - the aerogel even has a metallic shine. But in contrast to its conventional form, it is soft and malleable by hand. It consists of 98 parts air and only two parts of solid material. Of this solid material, more than four-fifths are gold and less than one-fifth is milk protein fibrils. This corresponds to around 20 carat gold.

Drying process a challenge
The scientists created the porous material by first heating milk proteins to produce nanometre-fine protein fibres, so-called amyloid fibrils, which they then placed in a solution of gold salt. The protein fibres interlaced themselves into a basic structure along which the gold simultaneously crystallised into small particles. This resulted in a gel-like gold fibre network.

"One of the big challenges was how to dry this fine network without destroying it," explains Gustav Nystrom, postdoc in Mezzenga's group and first author of the corresponding study in the journal Advanced Materials. As air drying could damage the fine gold structure, the scientists opted for a gentle and laborious drying process using carbon dioxide. They did so in an interdisciplinary effort assisted by researchers in the group of Marco Mazzotti, Professor of Process Engineering.

Dark-red gold
The method chosen, in which the gold particles are crystallised directly during manufacture of the aerogel protein structure (and not, for example, added to an existing scaffold) is new. The method's biggest advantage is that it makes it easy to obtain a homogeneous gold aerogel, perfectly mimicking gold alloys.

The manufacturing technique also offers scientists numerous possibilities to deliberately influence the properties of gold in a simple manner. "The optical properties of gold depend strongly on the size and shape of the gold particles," says Nystrom.

"Therefore we can even change the colour of the material. When we change the reaction conditions in order that the gold doesn't crystallise into microparticles but rather smaller nanoparticles, it results in a dark-red gold." By this means, the scientists can influence not only the colour, but also other optical properties such as absorption and reflection.

The new material could be used in many of the applications where gold is currently being used, says Mezzenga. The substance's properties, including its lighter weight, smaller material requirement and porous structure, have their advantages. Applications in watches and jewellery are only one possibility.

Another application demonstrated by the scientists is chemical catalysis: since the highly porous material has a huge surface, chemical reactions that depend on the presence of gold can be run in a very efficient manner.

The material could also be used in applications where light is absorbed or reflected. Finally, the scientists have also shown how it becomes possible to manufacture pressure sensors with it. "At normal atmospheric pressure the individual gold particles in the material do not touch, and the gold aerogel does not conduct electricity," explai

Nystrom G, Fernandez-Ronco MP, Bolisetty S, Mazzotti M, Mezzenga R: Amyloid Templated Gold Aerogels. Advanced Materials, 23 November 2015, doi: 10.1002/adma.201503465


Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only


.


Related Links
ETH Zurich
Space Technology News - Applications and Research






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

Previous Report
TECH SPACE
Plant defense as a biotech tool
Vienna, Austria (SPX) Dec 01, 2015
Defense strategies are not only important in chess or military tactics but also in nature. Especially plants are masters in this discipline. Some stone fruit, almond trees or even ferns defend their young buds against feeding pests with cyanide. The poison expels the greatest enemy. This is due to an enzyme called hydroxynitrile lyase (HNL), which can release molecularly stored hydrogen cyanide. ... read more


TECH SPACE
Gaia's sensors scan a lunar transit

SwRI scientists explain why moon rocks contain fewer volatiles than Earth's

All-female Russian crew starts Moon mission test

Russian moon mission would need 4 Angara-A5V launches

TECH SPACE
Mars Mission Team Addressing Vacuum Leak on Key Science Instrument

Letter to Mars? Royal Mail works it out for British boy, 5

European payload selected for ExoMars 2018 surface platform

ExoMars has historical, practical significance for Russia, Europe

TECH SPACE
A Year After Maiden Voyage, Orion Progress Continues

NASA's Work to Understand Climate: A Global Perspective

Australia seeks 'ideas boom' with tax breaks, visa boosts

Orion's power system to be put to the test

TECH SPACE
China's indigenous SatNav performing well after tests

China launches Yaogan-29 remote sensing satellite

China's scientific satellites to enter uncharted territory

China to launch Dark Matter Satellite in mid-December

TECH SPACE
Getting Into the Flow on the ISS

Orbital to fly first space cargo mission since 2014 explosion

Russian-US Space Collaboration Intact Despite Chill in Bilateral Ties

ISS EarthKAM ready for student imaging request

TECH SPACE
45th Space Wing supports NASA's Orbital ATK CRS-4 launch

Virgin Galactic Welcomes 'Cosmic Girl' To Fleet Of Space Access Vehicles

Orbital cargo ship blasts off toward space station

Aerojet Rocketdyne completes AJ60 solid booster for Atlas V launcher

TECH SPACE
What kinds of stars form rocky planets

Half of Kepler's giant exoplanet candidates are false positives

Exiled exoplanet likely kicked out of star's neighborhood

Neptune-size exoplanet around a red dwarf star

TECH SPACE
In-Space Manufacturing Prototype

Space Debris - A Growth Industry?

Russia's Kanopus-ST Research Satellite Deorbited, Heading to Earth

A new form of real gold, almost as light as air









The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us.