Gas permeability of carbon aerogels
- Chemistry and Materials Science Department, Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)
Carbon aerogels are synthesized via the aqueous polycondensation of resorcinol with formaldehyde, followed by supercritical drying and subsequent pyrolysis at 1050 [degree]C. As a result of their interconnected porosity, ultrafine cell/pore size, and high surface area, carbon aerogels have many potential applications such as supercapacitors, battery electrodes, catalyst supports, and gas filters. The performance of carbon aerogels in the latter two applications depends on the permeability or gas flow conductance in these materials. By measuring the pressure differential across a thin specimen and the nitrogen gas flow rate in the viscous regime, the permeability of carbon aerogels was calculated from equations based upon Darcy's law. Our measurements show that carbon aerogels have permeabilities on the order of 10[sup [minus]12] to 10[sup [minus]10] cm[sup 2] over the density range from 0.05--0.44 g/cm[sup 3]. Like many other aerogel properties, the permeability of carbon aerogels follows a power law relationship with density, reflecting differences in the average mesopore size. Comparing the results from this study with the permeability of silica aerogels reported by other workers, we found that the permeability of aerogels is governed by a simple universal flow equation. This paper discusses the relationship between permeability, pore size, and density in carbon aerogels.
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 5740853
- Journal Information:
- Journal of Materials Research; (United States), Vol. 8:12; ISSN 0884-2914
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CARBON
HYDRAULIC CONDUCTIVITY
POROSITY
GELS
PERMEABILITY
DENSITY
EQUATIONS
GASES
PYROLYSIS
SYNTHESIS
CHEMICAL REACTIONS
COLLOIDS
DECOMPOSITION
DISPERSIONS
ELEMENTS
FLUIDS
NONMETALS
PHYSICAL PROPERTIES
THERMOCHEMICAL PROCESSES
360606* - Other Materials- Physical Properties- (1992-)