A method is disclosed to fabricate carbon foams comprising a bicontinuous network of disordered or irregular macropores that are three-dimensionally interconnected via nanoscopic carbon walls. The method accounts for (1) the importance of wetting (i.e., matching the surface energies of fiber to sol) and (2) the viscosity of the microheterogeneous fluid filling the voids in the carbon paper. Carbon fiber papers are mildly oxidized by plasma etching, which greatly enhances the uniform uptake of resorcinol-formaldehyde (RF) mixtures. The RF solutions are oligomerized prior to infiltration and are cured into continuous polymeric webs that hang supported between adjacent carbon fibers; the polymer-fiber composites are pyrolyzed and retain a sponge-like morphology with 10-1000-nm pores and integrated electronic pathways.
Lytle, Justin C., Jeffrey W. Long, Amanda June Barrow, Matthew Paul Saunders, Debra R. Rolison, Jennifer L. Dysart
Naval Research Laboratory