Scientists are reporting the development of a new, ultra-light form of "frozen smoke" — renowned¹ as the world's lightest solid material — with amazing strength and an incredibly large surface area. The new so-called "multiwalled carbon nanotube (MCNT) aerogel（气凝胶） " could be used in sensors² to detect pollutants³ and toxic⁴ substances, chemical reactors⁵, and electronics components⁶. A report about the material appears in ACS Nano, a monthly journal. Lei Zhai and colleagues explain that aerogels made from silicon⁷ dioxide (the main ingredient in sand) and other material already are used as thermal⁸ insulation⁹（绝缘，隔离） in windows and buildings, tennis rackets, sponges to clean up oil spills, and other products. Aerogels are solid but so light that they have been compared to frozen smoke. However, only a few scientists have succeeded in making aerogels from carbon nanotubes, wisps of carbon so small that almost 50,000 would fit across the width of a human hair.

The report describes a process for making MCNT aerogels and tests to determine their properties. MCNT aerogels infused with（灌输） a plastic material are flexible, for instance, like a spring that can be stretched thousands of times. If the nanotubes in a one-ounce cube were unraveled and placed side-to-side and end-to-end, they would carpet three football fields. The MCNT aerogels also are excellent conductors of electricity, making them ideal for sensing applications, such as sensing as little as 0.003527 ounce of a material resting in the palm of one hand, the report indicates.