Scientists at the Paul Pascal Research Center in France have developed an industrial-scale method for low cost manufacturing of carbon aerogels from agglomerated carbon nanotubes.
According to the patent application (PDF), fabrication includes the following steps: (1) preparing an aqueous dispersion of carbon nanotubes in water in the presence of a dispersing agent; (2) forming a foam from the nanotubes aqueous dispersion of step (1) by bulking under the action of a gas in the presence of a foaming agent; and (3) freezing the foam obtained in step (2) and removing the water by sublimation.
What makes the manufacturing process inexpensive is the relative simplicity the researchers claim can be attained. It is carried out in an aqueous medium and, in general, does not involve rejects which are subject to specific treatments, which makes it a process which can be used on an industrial scale.
Scientists Renal Backov, Pierre Delhaes, Florent Carn and Celine Leroy say the carbon aerogels are particularly suitable for carrying out separations between solids and liquids. For example, they could be used as membranes or filtration materials for the filtration of blood or for the purification of waste water. And, given their specific structure, these aerogels might be used as biocompatible materials, especially as a support for cell growth.
The group says their aerogels can also be used for the storage of nonwetting liquid, especially for the storage of high-energy liquids in fuel cell membranes, or as the negative electrode in lithium batteries. They can also be used as sound or antivibration insulators.