Imagine one jacket that could keep you warm or cool, no matter the weather. Scientists at Stanford University have developed a reversible fabric that does just that, depending on which side is facing out.
The research team, led by Yi Cui, professor of materials science and engineering, was interested in developing ways to promote energy efficiency. Rather than heat or cool an entire building, it’s more efficient to outfit individuals with clothing that keeps them comfortable.
The scientists were inspired by transparent, water-impermeable kitchen wrap to create the cooling fabric; they developed an opaque and breathable material that has the ability to shuttle infrared radiation away from the body to promote cooling. Compared to cotton, the fabric kept artificial skin 2° C cooler in a laboratory test.
To create the warming fabric, the scientists sandwiched two layers of material with different abilities to release heat energy between layers of cooling polyethylene. On one side, a copper coating traps heat between the polyethylene layer and the skin; on the other, a carbon coating releases heat under another layer of polyethylene.
Worn with the copper layer facing out, the material traps heat and warms the skin. With the carbon layer facing out, it releases heat to stay cool. Combined, the sandwiched material can increase a person’s range of comfortable temperatures more than 10° F. The researchers predict the potential range could be as much as 25° F.
The next step is to develop a woven fiber with the heating/cooling properties needed to create consumer fabric and clothing. For more information, visit www.stanford.edu.