Totally rad: Radiative materials redefine cool clothes

The T-shirt looks just like others you might find in a clothing store. It is soft to the touch and pleasant to wear, with just the right stretch. But it feels noticeably cool on the skin. That’s because it uses a radical new way of lowering your temperature. Cotton fabrics circulate air to keep you comfortable, and athletic apparel wicks sweat away from skin. But this T-shirt, from the start-up i2Cool , does more: it transfers heat from your body to walls and furniture, even sending it straight into the cold depths of outer space. The shirt was designed by materials scientists to use the principle of radiative cooling : the natural process by which heat, or infrared (IR) radiation, flows from a hotter object to a cooler one. Martin Chu, CEO and cofounder of i2Cool, a spin-off from City University of Hong Kong, says the shirt lowers the wearer’s