Smart-building materials have come a long way in the last decade: They're less toxic, more durable and more energy efficient than their predecessors. But the smartest materials available today still can't accomplish something that even the most primitive life forms can do -- keep their internal environment stable as outside conditions change.
It's called homeostasis. Healthy humans, for example, maintain body heat of about 98.6 degrees as outside temperatures vary, manage their oxygen and carbon-dioxide levels and also keep their blood pressures, salt and sugar contents from falling too low or climbing too high. Even amoebas maintain their osmotic pressure at a livable rate. And cells in all living organisms manage their levels of ATP, the substance that enables the production and flow of energy internally from one set of biochemical reactions to another.
"If you look at living organisms, one of the most basic things they can all do is regulate their own internal conditions," says Ximin He, a post-doctorate fellow at the Harvard School of Engineering and Applied Science and the Hansjorg Wyss Institute for Biologically Inspired Engineering. "It's how organisms survive in different seasons and face the constant challenges life throws at them," she says.
Now researchers at Harvard University and the University of Pittsburgh -- including He -- hope to create a new class of materials that can do the same thing. After about two years of research, the scientists have come up with a platform for creating materials that can self-regulate many different factors, including temperature, light, pressure or pH balance. And they've already invented one prototype: a thin water-based gel, or hydrogel, that automatically heats up when it's cold (and stops heating when it isn't) to maintain a constant temperature.
The research, unveiled in Nature in July, could have huge implications for smart buildings. If future building materials could control their own temperatures, they might be able to eliminate the need for air conditioning and heating. Given that buildings account for nearly 39 percent of the U.S. energy use -- and heating, ventilation and air conditioning make up 64 percent of that 39 percent -- such a feat could significantly cut energy consumption and greenhouse-gas emissions.
It could also win these materials a piece of the booming sustainable-building market. Santa Monica, Calif.-based research firm IBISWorld expects the U.S. market will total $20.6 billion this year, up 7.3 percent from 2007, and reach $45.2 billion in five years.
Targeting corporate buildings
If self-regulating materials can truly deliver significant energy savings at a competitive cost, they have "great potential" to revolutionize the market for sustainable industrial and commercial buildings, said Deonta Smith, a construction and infrastructure analyst at IBISWorld. "It's a pretty innovative technology; pretty amazing," he says.
Cost will be a key factor determining whether self-regulating materials fulfill their potential. That could present a challenge, considering that new technologies usually cost more, Smith says. But if, aside from cutting energy bills, these materials can eliminate the cost of installing heating and air-conditioning ductwork and give companies more usable space in a building, they may be able to justify higher prices, he adds. "If it makes sense financially compared to other sustainable materials, then companies would be open to putting it in new construction," he says.
Next page: Technical challenges and market barriers