(FORTUNE Magazine) – Light bulbs that last half a century. Shoes whose insoles mold to the contours of our feet the minute we slip them on. Tiny blue lasers that enable a feature-length film to be stored on a single CD. Highway bridges wrapped in tough composites that won't rust or crumble.

These are some of the surprises in the making or already here as researchers inaugurate the age of made-to-order materials. They are beginning to understand the secrets of matter at the level of atoms--what makes diamonds so hard, say, or why tendons are amazingly supple and tough. Aided by supercomputers, the modern alchemists are using their new knowledge to create materials with novel combinations of properties. Exults Arthur N. Chester, senior vice president for research and technology at Hughes Electronics Corp.: "We can design materials and combinations of materials that never existed in nature, and construct them one atomic layer at a time." Such is the stuff that everything from new wireless communications to zippier car engines is made of.

Of course, manipulating molecules is far more complex than assembling Tinkertoys, and the new alchemists don't always get it right. Consider the vaunted Stealth bomber: Its radar-defeating paint quickly loses its concealing power when exposed to rain, heat, or humidity, according to a recent federal report. Using the $2 billion airplanes overseas will probably require sending along air-conditioned hangars.

But the made-to-order movement in materials science is ramping up fast. A few years ago, for example, physicist Marvin Cohen of the University of California at Berkeley predicted a new material, carbon nitride, if synthesized, might be harder than diamonds. Minute quantities of the stuff now have been made--though not yet enough to be tested for hardness.

Cohen's work shows how the new alchemists are using the abstract equations of quantum mechanics to touch our lives in concrete ways. He employs computerized models to investigate atoms' behavior at the fundamental level. That lets him predict the qualities of materials no one has ever seen--from new superconductors to diamondlike carbon nitride.

In other labs, scientists are copying nature to replicate the strength of spider silk, the stickiness of barnacles' glue, the toughness of abalone shells. By tinkering with ancient designs, they hope to create the supermaterials of the future.

FORTUNE recently took the measure of materials science in visits to more than a dozen labs across the United States.

SMART GELS M.I.T./CAMBRIDGE, MASS.

They swell, they shrink, they mold to human needs, all on cue. A gel, like the stuff that makes up the blobs below, is a mixture in which molecules form loose-linked networks to impart a degree of solidity. Jell-O, of course, is the best-known gel. Heat it, and the links between molecules quickly break, liquefying their network. But when such links are sturdier, as they are in new "smart" gels, the substances can do surprising things, such as temporarily get firmer when heated.

One family of novel gels includes materials that swell and shrink in response to heat, light, electricity--even magnetism. Unlike the "dumb" gels used in, say, diapers, which expand only slightly as they absorb moisture, these high-IQ ones will expand to 1,000 times their volume, then shrink to original size. The trick is to engineer the gels so they're balanced on a knife edge between forces of expansion and contraction. In one state, a smart gel's molecules may expel water; tweak it slightly, and it switches to water-loving mode.

Smart gels are already on the market--in the soles of golf shoes, which when heated by the foot conform for a perfect fit. Another likely use: coating for esophageal tissues damaged by stomach acid.

The guiding intelligence in smart gels is MIT physicist Toyoichi Tanaka. He has codified the principles by which gels operate and is co-founder of Gel Sciences, a Bedford, Mass., company spearheading new gel-based products.

BLUE LIGHT HEWLETT-PACKARD/PALO ALTO

In LEDs and--soon--lasers, blue is the color of money. More than any other high-tech field, optoelectronics owes its progress to materials that never existed in nature, fashioned one atomic layer at a time. Now sandwiches of exotic substances like indium gallium nitride and silicon carbide are making possible tiny, powerful new blue-light-emitting diodes (LEDs) and laser diodes (LDs), no bigger than a grain of salt.

Red and green LEDs and red LDs are commonplace: The LEDs serve as indicators on electronics gadgets, while CD players incorporate the LDs. But to build diodes that generate blue light is fiendishly difficult because the necessary materials require extreme temperatures and pressures. Hewlett-Packard and others in Japan and the U.S. recently succeeded in producing blue LEDs economically; combined with LEDs of other colors, they make possible big, sharp outdoor displays, huge TVs, and LED light bulbs that could last half a century.

Blue lasers could be bigger yet: By emitting light of much shorter wavelength than red lasers, they promise, for instance, to boost the capacity of CDs fivefold. Mastery of the materials suggests blue LDs are just a year or two away. Look for Nichia Chemical Industries of Anan, Japan, to offer them first: Shuji Nakamura, the wizard of blue-laser research, is an employee.

PLASTIC BRAINS BELL LABS/ MURRAY HILL, N.J.

Coming soon: the throwaway computer. Silicon--the stuff electronic circuits are made of--has an unlikely new rival: plastics. Using plastic akin to Mylar and a process like printing, experts at Lucent Technologies' Bell Labs have built circuits that can store data and handle rudimentary computing tasks.

Plastic computers will never displace Pentiums but could provide throwaway intelligence for use virtually anywhere: on luggage tags, visitor passes, even cereal boxes on grocery shelves. Hooked to substances with sensing or signaling capability, they could someday make objects seem alive: Imagine a vitamin bottle whose label reckons the expiration date, factoring in not just the pills' age but also the heat and damp to which they've been exposed.

Making plastic that conducts electricity depends on controlling the lengths of its polymers, or chains of molecules, which ordinarily vary widely. For now, experimenters use chemical synthesis; future electro-polymers may be bulk-produced by genetically reprogrammed bacteria. University of Massachusetts chemist David A. Tirrell has already harnessed the bacterium E. coli to produce sensing and signaling polymers that can detect the presence of an insecticide.

ERSATZ SILK CORNELL UNIVERSITY/ITHACA, N.Y.

In ultrastrong fiber, spiders are still the creatures to beat. Evolution got there first in designing ultrastrong materials; specialists in "biomimetics" try to copy and improve on nature's work. Hence the abalone shell is a model for tank-armor designers, while gluemakers strive to outdo the barnacle, which exudes the world's stickiest underwater glue. For fiber makers, Florida's golden orb spider is the creature to beat. While humans need acids, high temperatures, and factories to make strong fiber, the spider spins silk stronger than steel in a room-temperature aqueous solution.

Researchers at Cornell aim to change that. To collect spinnings for analysis, they "silk" each of their spiders for 45 minutes three times a week. First a researcher tapes a spider ingloriously to a lab bench and examines its silk organs with a microscope. Usually a strand is protruding; the researcher grabs it with tweezers and ties it to a rotating drum that extracts silk at more than two inches per minute.

To decode the structure of the silk, researchers slip radioactive tracers into the spiders' food. The goal is to synthesize genes that will yield fiber even stronger than the spiders'. At first, researchers plan to reprogram bacteria to produce silk; eventually, they hope to use plants. Tobacco is a candidate, making spider silk a possible lifeline for an embattled industry.

COMPOSITES XXSYS TECHNOLOGIES/SAN DIEGO

Cold War fibers now defend against quakes. In the Cold War, carbon fiber and other high-tech composites were confined largely to advanced military applications because of the materials' high cost. Now composites are finding their way into everyday use: from building ships, railcars, and other products to strengthening freeways.

In California, where quake-proofing bridges and highways is big business, XXsys Technologies uses carbon fiber to steal market share from steel. When a quake hits, a highway's support columns are typically what give way. By sheathing them in composites, XXsys boosts their resilience and protects them from erosion by sun and rain.

XXsys employs the same type of composites used in state-of-the-art airliner parts, such as floor beams. The company's secret weapon is the "robowrapper," a wrap-and-heat system that can coat columns up to seven feet in diameter. Starting at the base and inching upward, the machine winds threadlike carbon fibers from 12 spools onto the column in six-foot installments. Right behind the wrapper comes an oven, which encloses each new section and heats it until, after an hour, the composite is cured. Talk about a peace dividend: It's nice to think that you're driving your kids over bridge pillars as modern as a Boeing 777.

Composites are finding their way into a surprising range of uses. Among the most novel: a railroad boxcar, molded by a Du Pont joint venture, that works like a giant picnic cooler. With no need for refrigeration, it can keep an entire load of freshly bottled beer cold on a coast-to-coast trip.

REPORTER ASSOCIATE Alicia Hills Moore