Nanofiber single-fiber characterization

In the following sections, selected characterization tests based on several common anticipated uses for nanofiber materials are presented. The assessment of interstitial porosity properties, analysis of fiber dimension by microscopy, and mechanical integrity of fiber mats are the more important metrics in several application areas. Some of these will eventually be adopted as standard test methods in the field — both the American Sodely for Testing Materials (ASTM) and the International Standards Organization (ISO) have initiated efforts to standardize the nomenclature and test methods relating to nanomaterials, including nanofibers. Here, the reader wiU be afforded a flavor of the rather limited research literature on single-fiber measurements. 

A test matrix of about 20 different carbon samples, including commercial carbon fibers and fiber composites, graphite nanofibers, carbon nanowebs and single walled carbon nanotubes was assembled. The sorbents were chosen to represent a large variation in surface areas and micropore volumes. Both non-porous materials, such as graphites, and microporous sorbents, such as activated carbons, were selected. Characterization via N2 adsorption at 77 K was conducted on the majority of the samples for this a Quantachrome Autosorb-1 system was used. The results of the N2 and H2 physisorption measurements are shown in Table 2. In the table CNF is used to designate carbon nanofibers, ACF is used for activated carbon fibers and AC for activated carbon. 

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