As part of a research initiative, Naval Postgraduate School (NPS) Department of Mechanical and Aerospace Engineering associate professor Claudia C. Luhrs, with Department of Physics research professor Jonathan Phillips and a team of student researchers, recently designed carbon nano-fiber foams (CFF), materials with the potential for multiple military and civilian applications. The foams, formed solely of intertwined carbon fibers, are lightweight, temperature resistant and hydrophobic with the appearance and viscoelastic properties of a polymeric foam.

Luhrs notes that other researchers have created foam-like structures from carbon nanotubes, but those structures were fragile and required added polymers to prevent them from disintegrating. The NPS team was able to demonstrate, for the first time, that CFF can behave as a viscoelastic solid with stable mechanical properties without the need of a polymeric component.

“[Combining carbon nano-materials] with polymers imprints undesired characteristics in the product such as reduced conductivity and low thermal stability due to the use of polymeric matrices,” says Luhrs. The NPS-developed CFF demonstrated high electrical conductivity, low density and stability under high temperatures without the added polymers.

Phillips noted that the team showed that the material has potential for use as the sensing material in a strain sensor since it presents a linear relationship between resistance and strain. The foam shows promise for civilian industrial applications, as it can absorb environmentally-damaging liquids like crude oil while repelling water. CFF also does not pose the same inhalation risks as other carbon-based materials, which could improve safety in CFF applications.