World's lightest solid material, known as 'frozen smoke', gets even lighter
By Grant Banks
January 13, 2011
Researchers have created a new aerogel that boasts amazing strength and an incredibly large surface area. Nicknamed ‘frozen smoke’ due to its translucent appearance, aerogels are manufactured materials derived from a gel in which the liquid component of the gel has been replaced with a gas, resulting in a material renowned as the world’s lightest solid material. The new so-called “multiwalled carbon nanotube (MCNT) aerogel” could be used in sensors to detect pollutants and toxic substances, chemical reactors, and electronics components.
Although aerogels have been fabricated from silica, metal oxides, polymers, and carbon-based materials and are already used in thermal insulation in windows and buildings, tennis racquets, sponges to clean up oil spills, and other products, few scientists have succeeded in making aerogels from carbon nanotubes.
The researchers were able to succeed where so many before them had failed using a wet gel of well-dispersed pristine MWCNTs. After removing the liquid component from the MWCNT wet gel, they were able to create the lightest ever free-standing MWCNT aerogel monolith with a density of 4 mg/cm3.
MWCNT aerogels infused with a plastic material are flexible, like a spring that can be stretched thousands of times, and 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 MWCNT aerogels are also excellent conductors of electricity, which is what makes them ideal for sensing applications and offers great potential for their use in electronics components.
A report describing the process for making MWCNT aerogels and tests to determine their properties appears in ACS Nano.