51动漫

Editorial: 鈥�Are we in the Metamaterial Age?鈥�

See more in our gallery: 鈥�Know your stuff: Collect our pick of material wonders鈥�

THE STRANGER鈥橲 muscles strained against his shirt as he hefted the briefcase handcuffed to his wrist. 鈥淲anna see what I鈥檝e got?鈥� he asked in a low Texan drawl, inviting the woman to follow him to a place where 鈥渘o one would get hurt鈥�.

To someone less worldly wise than Zoe Laughlin, this encounter at a conference in San Antonio might have seemed a little sinister. For her, though, it is all part of the job. Laughlin is one of a team at University College London鈥檚 that is building up 鈥渁 wonder chamber that celebrates the material world鈥�. The Materials Library, which is due to open this week, includes crying metals, a sponge for comet dust, living concrete 鈥� and the contents of a handcuffed Texan鈥檚 briefcase.

The idea started with Laughlin鈥檚 colleague . In the early 2000s he was just down the road at King鈥檚 College London, where he had a semi-famous office drawer. 鈥淧eople started visiting just to look at what was in the drawer, not to visit me,鈥� he says.

Inside was an eclectic mix of materials he had collected. One was a wafer of aluminium nitride. Typically found inside electronic devices, this pale, smooth material performs a party trick beloved of materials scientists. Its thermal conductivity is unusually high, so if you pick up a wafer, it shuttles heat from your hand. Brush its edge across an ice cube, and the wafer will melt the ice and cut clean through it.

In 2005, Laughlin, then an artist with an interest in materials, was passing Miodownik鈥檚 office when she noticed a poster on his door for an exhibition she was planning to go to. The two really hit it off when Laughlin revealed she also owned a cache of strange stuff: cork, sugar cubes, hair. Eventually, along with designer of Goldsmiths, University of London, they decided to build a much bigger collection.

Several privately run material repositories and databases aimed at artists and architects have emerged in the past few years. Materia, based in the Netherlands, has a . has collections in New York and elsewhere. But Conreen, Laughlin and Miodownik had a different ambition: to build a collection that speaks of the changing relationship between humans and the things we make and use. 鈥淢aterials are like characters in a book. They tell the story of civilisation,鈥� says Miodownik. Every time we find a new way of rearranging atoms, it changes what we can do: sometimes in a small way, sometimes by defining an age in bronze, steel or silicon.

The first incarnation of the Materials Library, deep in a basement of King鈥檚 College, did justice to that history. When 51动漫 visited last year, it was like a Victorian apothecary鈥檚 shop with its racks of tiny vials, as well as a drawer full of fluorescent things and shelves packed with strange objects 鈥� a lump of raw rubber, a Bakelite telephone, a radioactive fruit bowl made from uranium glass.

The expanded library has roughly 1500 materials, and counting. Among Laughlin鈥檚 highlights is silica aerogel, one of the world鈥檚 lightest solids. 鈥淚t makes a squeaky sound like polystyrene,鈥� she says. 鈥淎nd it鈥檚 beautiful.鈥� Dubbed blue smoke, it appears strangely fuzzy owing to the way it scatters shorter wavelengths of light. NASA in the spacecraft, which rendezvoused with comet Wild 2 in 2004. The material鈥檚 excellent thermal insulation properties have since seen it spun out into architectural uses.

Squishy and impermanent

Then there is self-healing concrete. If a tiny crack forms in a building made of this stuff, water seeping in will activate dormant Bacillus bacteria, which produce calcite and seal the gap. The material鈥檚 inventors, at the Delft University of Technology in the Netherlands, hope to commercialise it in the next two or three years.

The materials in the library are not categorised in traditional groups like metals or plastics. Instead, they are simply ordered according to when they were collected; first on the inventory is a set of jars containing all the elements of the periodic table. The idea is that they can be browsed according to more human factors like squishiness, danger, impermanence, the red ones and so on.

Take tin. It is a metal, and malleable 鈥� but you could also class it as 鈥渘oisy鈥�. Bend a bar and you will hear a 鈥�. 鈥淪uddenly you鈥檙e down at the microscopic level asking why,鈥� says Laughlin. The answer lies in the hexagonal shape of the metal鈥檚 layered crystals. As the bar flexes they do not slide over each other smoothly, but jump and grind.

Such unquantifiable characteristics, along with subjective factors of feel, taste and smell, have often been ignored, says Miodownik. That doesn鈥檛 matter for designers of jet engines, but it can for materials inside buildings, on consumer gadgets or woven into clothes. An architect might want to create a space that feels 鈥渨arm鈥�, for example, or a clothes designer might want to know what new materials will feel like without trying them all on. The library鈥檚 curators are pioneering studies of the properties of materials 鈥� how our subjective perceptions of them relate to well-known, measurable properties.

One of their findings is that the perceived warmth of wood compared with metal reflects the wood鈥檚 lower thermal effusivity, essentially a measure of how quickly it transfers heat. A little less obviously, perception of hardness is linked to a material鈥檚 elastic modulus, which quantifies how it deforms (). The idea is that a designer selecting a material to elicit a particular sensory response might use this knowledge as a shortcut.

Access to the library will initially be by appointment, with monthly open days. Visitors will be encouraged to contribute to the sensoaesthetic research by touching, sniffing and even licking the materials.

鈥淰isitors to the library will be encouraged to touch, sniff and even lick the materials鈥�

And what of the mysterious Texan? Once he and Laughlin were in a safe place 鈥� a sports hall attached to the conference venue 鈥� the man unclipped his case to reveal a set of polished black spheres the size of snooker balls.

Any doubt as to their identity was dispelled when the stranger launched one at the wall. Chips flew off the bricks, yet as the ball thudded to the floor, its surface was as smooth as ever. The ball was made of silicon nitride, a substance whose hardness makes steel seem like putty, and which has an incredibly low-friction surface. Oil companies use small spheres of the stuff as bearings in high-pressure drills, as did NASA inside the space shuttle engine. Each black globe was worth thousands of dollars 鈥� hence the stranger鈥檚 handcuffs.

鈥淲anna bit?鈥� he asked Laughlin with a grin. She did.

This article appeared in print under the headline 鈥淭hat鈥檚 the stuff鈥�