Sunday, June 3, 2007

35. Catalysts/Mordants/Surfactants


Mark said...

Water softening

Citric acid's ability to chelate metals makes it useful in soaps and laundry detergents. By chelating the metals in hard water, it lets these cleaners produce foam and work better without need for water softening. Similarly, citric acid is used to regenerate the ion exchange materials used in water softeners by stripping off the accumulated metal ions as citrate complexes.

Mark said...

It's an insulator, retardant, purifier, catalyst, remediator, war material (perhaps to make wars impossible actually, if you think about it--indestructible things so humans applying violence to each other might be rendered useless--if equally supplied of course) and building material all rolled into one:


[Several other building materials are mentioned in this post as well, most of them not retardants though insulators instead]

from The Sunday Times
August 19, 2007
Scientists hail ‘frozen smoke’ as material that will change world

Image :3 of 3

Videos: Aerogel in the wild | 'The stuff of dreams': Aerogel in architecture | Peter Stothard on Aerogel, frozen smoke and Rupert Brooke |

A MIRACLE material for the 21st century could protect your home against bomb blasts, mop up oil spillages and even help man to fly to Mars.

Aerogel, one of the world’s lightest solids, can withstand a direct blast of 1kg of dynamite and protect against heat from a blowtorch at more than 1,300C.

Scientists are working to discover new applications for the substance, ranging from the next generation of tennis rackets to super-insulated space suits for a manned mission to Mars.

It is expected to rank alongside wonder products from previous generations such as Bakelite in the 1930s, carbon fibre in the 1980s and silicone in the 1990s.

Mercouri Kanatzidis, a chemistry professor at Northwestern University in Evanston, Illinois, said: “It is an amazing material. It has the lowest density of any product known to man, yet at the same time it can do so much. I can see aerogel being used for everything from filtering polluted water to insulating against extreme temperatures and even for jewellery.”

Aerogel is nicknamed “frozen smoke” and is made by extracting water from a silica gel, then replacing it with gas such as carbon dioxide.

The result is a substance that is capable of insulating against extreme temperatures and of absorbing pollutants such as crude oil.

It was invented by an American chemist for a bet in 1931, but early versions were so brittle and costly that it was largely consigned to laboratories.

It was not until a decade ago that Nasa started taking an interest in the substance and putting it to a more practical use.

In 1999 the space agency fitted its Stardust space probe with a mitt packed full of aerogel to catch the dust from a comet’s tail. It returned with a rich collection of samples last year.

In 2002 Aspen Aerogel, a company created by Nasa, produced a stronger and more flexible version of the gel. It is now being used to develop an insulated lining in space suits...

Mark Krajewski, a senior scientist at the company, believes that an 18mm layer of aerogel will be sufficient to protect astronauts from temperatures as low as -130C. “It is the greatest insulator we’ve ever seen,” he said.

Aerogel is also being tested for future bombproof housing and armour for military vehicles. In the laboratory, a metal plate coated in 6mm of aerogel was left almost unscathed by a direct dynamite blast.

It also has green credentials. Aerogel is described by scientists as the “ultimate sponge”, with millions of tiny pores on its surface making it ideal for absorbing pollutants in water.

Kanatzidis has created a new version of aerogel designed to mop up lead and mercury from water.

Other versions are designed to absorb oil spills.

He is optimistic that it could be used to deal with environmental catastrophes such as the Sea Empress spillage in 1996,

[the best way to 'deal with' that is to get rid of oil, period! See "Energy" category.]

when 72,000 tons of crude oil were released off the coast of Milford Haven in Pembrokeshire.

Aerogel is also being used for everyday applications. Dunlop, the sports equipment company, has developed a range of squash and tennis rackets strengthened with aerogel, which are said to deliver more power.

Earlier this year Bob Stoker, 66, from Nottingham, became the first Briton to have his property insulated with aerogel. “The heating has improved significantly. I turned the thermostat down five degrees. It’s been a remarkable transformation,” he said.

Mountain climbers are also converts. Last year Anne Parmenter, a British mountaineer, climbed Everest using boots that had aerogel insoles, as well as sleeping bags padded with the material. She said at the time: “The only problem I had was that my feet were too hot, which is a great problem to have as a mountaineer.”

However, it has failed to convince the fashion world. Hugo Boss created a line of winter jackets out of the material but had to withdraw them after complaints that they were too hot.

Although aerogel is classed as a solid, 99% of the substance is made up of gas, which gives it a cloudy appearance.

Scientists say that because it has so many millions of pores and ridges, if one cubic centimetre of aerogel were unravelled it would fill an area the size of a football field.

Its nano-sized pores can not only collect pollutants like a sponge but they also act as air pockets.

Researchers believe that some versions of aerogel which are made from platinum can be used to speed up the production of hydrogen. As a result, aerogel can be used to make hydrogen-based fuels.

* Read all 228 comments


From The Times
November 16, 2005
It's the stuff of dreams
Could buildings one day be made of carbon?

Tom Dyckhoff

Mark Miodownik got a box from Nasa the other day. It contained aerogel, the lightest solid on earth. You can barely feel it, save for a slight warmth on your palm.

It’s an insulator, but was mainly used by Nasa for collecting space dust — it’s so light that even the tiniest coating is detectable.

Dr Miodownik likes it, though, for its aesthetics. It’s like bath foam, he explains, “but imagine the bubbles are a nanometre wide”, and, like bath foam, it has a blue iridescence and rainbow refraction.

“I could gaze at it all day. Imagine a building coated in it.”

Dr Miodownik, a materials scientist at King’s College London, has a vast store cupboard of these goodies — “like a giant sweet shop, and I’m in charge”.

The Engineering Art Materials Co-operative is a library not of books but of materials, both sci-fi, such as aerogel, and more commonplace, though equally amazing. Here’s tungsten, “what they make light-bulb filaments from”, only a big fist of it — “people are astonished how heavy it is”.

The point of Dr Miodownik’s sweet shop is to inspire architects, artists and designers. “These materials shouldn’t be gathering dust in science departments. They should be out there,” he says.

Engineering Art is in part a dating agency between creatives and science, through events that Dr Miodownik organises at Tate Modern to get architects, artists and designers just to feel materials, to “innovate through their fingers”, learn their properties and get them “out there” on buildings.

Their obsession with novelty means that architects are as sensitive to trends as schoolkids. Right now you can’t move for buildings made from Cor-Ten steel and ETFE, the first a metal that intentionally rusts to a rich red, the second a cladding material like bubble wrap — the Eden Project is covered in it and the world’s largest ETFE building, the national swimming centre, is being built for the Beijing Olympics.

However, “conservatism is the overriding character of the building industry,” says Graham Dodd, an associate director at Arup, the world’s most innovative engineers. “So technological innovation happens incredibly slowly.”

Dodd’s department scours the globe for new components for buildings.

“There may be technologies or materials that seem new in architecture,” he says, “but by the time they’ve reached us they’re old news.”

Architects have long fantasised about the industrial production of buildings as if they were cars or boats. Future Systems famously used boat manufacturers to construct the Media Stand at Lords because there simply wasn’t the expertise within the building industry.

Today computer-aided design means that architects can dream faster and wilder than ever. Dodd spends much of his time perfecting double curved glass panels to create seamless blobs. Engineering, the actual making of the buildings, and the things they are made from are having to catch up fast with imaginations.

In fact, says Dodd, “we are on the foothills of the most exciting period of technological change since the 1960s”.

Fugitive Materials: The Art and Science of Impermanence, with Mark Miodownik, Cornelia Parker and others, takes place at Tate Modern, SE1 (020-7887 8888), on Nov 29 at 6.30pm.

Bye, bye brick? The future of building


Áron Losonczi, a Hungarian architect, laid glass fibres into structural concrete blocks before they set, rendering the light ethereal and see-through.


Used to insulate spaceships 30 years ago, Nanogel — sound absorbent, insulating and light transmitting — is now sandwiched within building facades.


American architects have invented a new façade material made from paper-thin, polymer-based film, stuffed with air gel pockets for insulation. It can be attached with flexible solar cells and LEDs, printed with patterns and wrapped around a frame.

Electrochromic glass

We already have glass that becomes opaque by running an electric current through it. More sophisticated versions change reflectivity, glare, colour and opacity: entire glass-clad buildings might act like Reactolite sunglasses, and reducing the heat gain and loss that can make glass so energy inefficient.

Responsive environments

Spaces that communicate with their user have been one of architecture’s dreams since the Sixties. One day walls will be soft, embedded with sensors and IT, so that walls become like skin, buildings like bodies. Coating walls in nanotechnology devices is being explored too, for instance to make surfaces self-cleaning — or coating them in electronic ink so that a wall becomes one giant LCD screen. The first small SmartSlab panels will emerge in the next three years.

Carbon fibre

Imagine a skyscraper, 40 storeys high, with a helical shell entirely woven by robots from IT-embedded carbon fibre, like a cocoon. The LA architects Peter Testa and Devyn Weiser are pioneering the transfer of carbon fibre technology to architecture. Most of their projects, like the Carbon Tower, remain speculative.