Properties that influence the specific surface areas of carbon nanotubes and nanofibers.
Birch-ME; Ruda-Eberenz-TA; Chai-M; Andrews-R; Hatfield-RL
Ann Occup Hyg 2013 Nov; 57(9):1148-1166
Commercially available carbon nanotubes and nanofibers were analyzed to examine possible relationships between their Brunauer-Emmett-Teller specific surface areas (SSAs) and their physical and chemical properties. Properties found to influence surface area were number of walls/diameter, impurities, and surface functionalization with hydroxyl and carboxyl groups. Characterization by electron microscopy, energy-dispersive X-ray spectrometry, thermogravimetric analysis, and elemental analysis indicates that SSA can provide insight on carbon nanomaterials properties, which can differ vastly depending on synthesis parameters and post-production treatments. In this study, how different properties may influence surface area is discussed. The materials examined have a wide range of surface areas. The measured surface areas differed from product specifications, to varying degrees, and between similar products. Findings emphasize the multiple factors that influence surface area and mark its utility in carbon nanomaterial characterization, a prerequisite to understanding their potential applications and toxicities. Implications for occupational monitoring are discussed.
Nanotechnology; Analytical-processes; Chemical-properties; Physical-properties; Hydroxy-compounds;
Author Keywords: BET-specific surface area; carbon nanotube; nanofiber; nanomaterial
M. Eileen Birch, National Institute for Occupational Safety and Health, Division of Applied Research and Technology, MS-R7 4676 Columbia Parkway, Cincinnati, OH 45226
Annals of Occupational Hygiene