Coffee Drinkers, Say Hello to Scald-Proof Nanofabric
Anyone who's ever spilled a hot beverage in his or her lap will be happy to hear that chemists at the University of Minnesota have announced a scaldproof fabric. Water-resistant fabric, of course, has already existed for some time -- but its impermeability applies only to cool liquids. Hot coffee, scalding soup, and other liquids above a certain temperature, on the other hand, seep right through water-resistant cloth. Why the difference? Water-repellant surfaces -- whether natural, like a lotus leaf, or man-made, like a raincoat -- work in two ways. A waxy hydrophobic coating inhibits water penetration, and a spiky texture traps air under water droplets, which limits the amount of contact the water will have with the surface. As a result, droplets remain near-spherical and roll off. With scalding liquids, however, problems set in: not only do they cause the waxy coating to melt, but...