6.08: Features

Archive | 6.08 - Aug 1998 | Features

Smart Parts
By Mark Frauenfelder

A user's guide to out-of-the-box living.

In Merlin's day, materials science got a lot more respect. People don't think much about materials today. No one really cares about titanium for titanium's sake, though the metal alloy is a household word, thanks to mountain biking and Frank Gehry. Yet materials are the substance of our world: They surround us, giving our environment form, our habitats structure. Every year, humans pull 15 billion tons of raw materials from the earth - 30 trillion pounds of rock, wood, metal, and petroleum extracted to synthesize thousands of products.

But in an age in which we can make diamonds out of peanut butter, why is your habitat built of the same types of materials used by your great-grandparents? Because traditional construction materials have withstood the test of time. Though houses built of wood and brick may splinter, glass windows may shatter, and shake roofs may kindle, those materials have predictable properties. Worried about lawsuits, architects and builders opt for materials with a track record.

But there is new stuff out there. Latter-day Merlins, working quietly in government research labs and universities, large petrochemical concerns, and small no-name companies, are creating - sometimes stumbling upon - substances that are strong yet flexible, smart, durable, and environmentally sound (a trait past wizards did not find it necessary to consider). New architectural and construction elements will make stronger, lighter, cheaper, and smarter domiciles that are closer to Le Corbusier's dictum: "A house is a machine for living in." After all, shouldn't the smartness be built into the house itself, rather than confined to the coffee machine?

Liquid drapes

Peeping Toms can blame it on liquid crystal - a substance we associate with digital watches, calculators, and other consumer-electronics products with display screens. LCDs are everywhere because the material does a simple but eminently useful thing: It reacts visibly to magnetic and electrical fields. It has an on color and an off color.

About five years ago 3M (legendary birthplace of Post-it Notes) developed paper-thin, electrically sensitive Privacy Film, based on patents held by Kent State University and Raychem Corporation. Today Viracon, an architectural-glass company, sandwiches a layer of liquid crystals between two sheets of 3M's film, which in turn are held between panes of glass. When electricity is applied to the film, the liquid crystals line up and the foggy material becomes clear. When the current is withdrawn, it becomes opaque again. The result: Privacy Glass. Now you see through it - now you don't.
Viracon: www.viracon.com/.

Bulletproof vestibule

Paltech informational videos feature 200-mph tornadoes, flying debris, bullets, and even a bomb test - but no broken glass. That's the point of Paltech, a hurricane-resistant window material sold by Security First Distributors: Now people in glass houses can throw stones with abandon.

The secret of the shatterproof material is polycarbonate, a family of plastics 250 times stronger than glass. Hit a sheet of this stuff with a sledgehammer and it won't break. Yet, illogically, the material can be scratched by a key. To protect the delicate surface, Security First sandwiches the polycarbonate between sheets of glass, creating an unbreakable material that weighs half as much as standard panes. The caveat: Paltech is expensive, and - much to the chagrin of our glass-obsessed architects (see "Windows 99," page 114) - the cost of a Paltech palace would be prohibitive.
Security First Distributors: www.securitywindow.com/.

It's metal! It's fabric! It's Flectron!

George Beylerian knows fabrics. And he loves metalized nylon. The founder of an obsessive, almost fetishistic art resource and gallery in New York City called Material ConneXion (www.materialconnexion.com/), Beylerian first encountered the substance at the Tech Textil show in Germany last year. The lightweight pliable fabric has the feathery sheen of a FedEx envelope, because both materials are made by bonding fibers in a random configuration, rather than weaving them.

Metalized nylon - as the name implies - consists of thin nylon fibers coated in copper or silver. "It's a hybrid material with the appearance of paper and the properties of a fabric," he explains. "It's tearproof and fireproof." More important, the fabric shields spaces against electromagnetic interference that would damage electronic equipment and erase digital data. Manufactured and sold as Flectron by Advanced Performance Materials, the substance is used in door, window, screen, and partition construction.
Advanced Performance Materials: www.apm-emi.com/.

Out of thin air
It started with a wager: During the 1930s, a researcher named Stephen Kistler bet a colleague that he could make a gel that didn't shrivel up when it dried. He won the bet with aerogel, aka frozen smoke. Kistler's flammable recipe was so dangerous, however, that the material didn't break out of R&D until a UC Berkeley professor discovered a safer production process 50 years later. Now, in the '90s, it is finally being commercialized.

Made from a maze of silica strands only one one-thousandth the thickness of a human hair, the substance is 95 to 99 percent empty space and weighs only three times as much as air, yet a one-pound block can support half a ton. Why should you care? Because aerogel is an amazing insulator: A thin sheet of this nearly translucent material insulates better than yards of cotton-candy-colored fiberglass batting.

Aerogel kept the electronic innards of the Mars Rover toasty warm, even when Martian surface temperatures dropped to minus 88 degrees Fahrenheit. Although aerogel isn't fully transparent (something researchers are working to correct), it is already used to produce windows and skylights that insulate better than the surrounding walls. In Ontario, Canada - where people don't have to be told why they should care about insulation - AMI, a start-up, is planning to produce 250,000 square feet of aerogel a year to replace local-standard three-pane glass windows, which still don't keep the frost out.

Manufacturers have a favorite trick to show aerogel's heat-holding prowess: They place a hand against a thin sheet and apply a blowtorch to the other side. No sweat.
NASA: snail.msfc.nasa.gov/station/train/Aerogel/HOUSEOFFUTURE.HTML.

Building a greater wall

Cement surrounds us - in foundations, floors, and interior walls. First used in ancient Roman constructions such as the Pantheon, then lost during the Middle Ages and rediscovered by English engineer John Smeaton during the 18th century, cement is one of the oldest building materials and one of the most common. The substance is formed by crushing, blending, and heating limestone and clay until it almost fuses. Then it is ground again into a fine powder. When mixed with water, the silicates and aluminates in the ingredients undergo a chemical reaction and begin to harden into a solid mass. But if water permeates the material before it has fully set (which can take years), the concrete can crack.

In their quest to develop a leach-proof material for storing nuclear waste, Los Alamos National Laboratory researchers created a stronger and more chemically stabile cement. The process, based in part on the patents of The Supramics Company, uses high-pressure supercritical carbon dioxide - that is, CO2 in a state between liquid and gas - to chemically alter the cement and drive out the water. This process transforms it into pure limestone, a virtually indestructible material, in a matter of hours. By comparison, the cement in the Great Wall of China - parts of which were built during the fourth century BC - has not fully hardened, and won't for another 30,000 years.
The Supramics Company: www.supramics.com/.

Vegetable, mineral, material

Sure, soybeans can be transformed into everything from milk to faux filet mignon. But a soy-based building material? In fact, Henry Ford made the first fiberglass-soybean auto body in 1938. And biocomposites have come a long way since then. These materials, composed of renewable or recycled biological substances, are inexpensive, lightweight, and eco-friendly. Take Environ: A slab of this substance - made of soy flour and recycled newsprint - has the properties of wood and the look of granite. The material, manufactured by Phenix Biocomposites, is harder than oak and can be milled, sawed, drilled, and nailed. Other biocomposites - made from wheat or rice straw or dust from rock quarries - imitate and replace nonrenewable materials or those derived from scarce natural resources.
Phenix Biocomposites: www.phenixmfg.com/.

Mood paint

This is not the stuff of science fiction or even structural engineering. It's just paint - the home-improvement staple mixed with a thermochromic carbon-based pigment that fades as the temperature rises and brightens as it cools. NASA developed the substance as a coating that would warn scientists when a machine was overheating. Researchers also hoped that the material could be used as an exterior house paint that would darken and absorb heat from sunlight during colder seasons. But the paint is not UV protected and costs too much to affect energy efficiency.

So, for the moment, it's just the stuff of art: Jürgen Mayer Hermann, a German artist, mixed the thermosensitive pigment with latex house paint to create his Housewarming installation. When you touch the wall, the color temporarily fades, leaving a sort of negative shadow. Functional? Perhaps not, but fabulous nonetheless.
Henry Urbach Architecture: +1 (212) 627 0974.

Urban band-aid

Think outside the box of your house for a moment. Think about the habitat at large - towns, cities, and the roads that connect them. According to Antonio Nanni, a professor of civil engineering at the University of Missouri, almost half of the 575,600 highway bridges in the US are structurally deficient or functionally obsolete. But Nanni has a band-aid solution: a carbon-fiber reinforced polymer system. Eight times stronger than conventional reinforcing steel, this composite is formed into sheets and wallpapered over damaged concrete foundations and structures.

Now, think about what the technology can do for the foundation of your house.
Antonio Nanni: +1 (573) 341 4400.

Faux photosynthesis

Greg Van Patten may be the only materials scientist who claims chlorophyll as his muse. A bioscience researcher at Los Alamos National Laboratory, Van Patten is developing films that could be used to coat roofing tiles.Dyes in the film would imitate photosynthesis, collecting energy from the sun and converting it to electricity.

On a clear day, the sun transmits about a kilowatt of power per square meter. While plants use that energy to convert water and CO2 into food, Van Patten's tiles can use the energy to power your VCR or Mr. Coffee - and we're talking about hours of video and many pots of coffee. Traditional semiconductor solar cells collect only a limited portion of the light spectrum, but the Los Alamos tiles are treated with layers of films, each tinted with a dye designed to absorb a particular wavelength of light. A stack of different-colored layers can soak up many wavelengths of light.
Los Alamos National Laboratory: www.lanl.gov/.

Smart walls

If Thomas Edison is the father of electricity, then Deborah Chung, a professor of mechanical and aerospace engineering at the State University of New York at Buffalo, is the mother of structural electronics. As you might expect, the technology embeds electronic properties into materials so that surfaces will be able to store electricity and will have the intelligence to measure and control climate. Chung's team has built several prototypes.

The breakthrough-within-a-breakthrough: Material - carbon fibers bound by an epoxy matrix - that acts as a metal and a semiconductor. Less expensive, less fragile, and easier to produce than silicon circuitry, structural electronics will allow walls to store energy and act as control circuitry. The carbon fibers can also be used to create smart concrete that will sense and report structural damage.
Deborah Chung: +1 (716) 645 2593.

Contributing editor Mark Frauenfelder wrote "Transformer" in Wired 6.06.