Browsing by Author "Parra-Vasquez, Nicholas A. G."

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    Method and apparatus for determining the length of single-walled carbon nanotubes
    (2005-11-08) Pasquali, Matteo; Davis, Virginia Angelica; Stepanek-Basset, Ingrid; Parra-Vasquez, Nicholas A. G.; Hauge, Robert H.; Rice University; United States Patent and Trademark Office
    The present invention is directed to at least one method and at least one apparatus for determining the length of single-wall carbon nanotubes (SWNTs). The method generally comprises the steps of: dispersing a sample of SWNTs into a suitable dispersing medium to form a solvent-suspension of solvent-suspended SWNTs; determining the mean SWNT diameter of the solvent-suspended SWNTs; introducing the solvent-suspended SWNTs into a viscosity-measuring device; obtaining a specific viscosity for the SWNT solvent-suspension; and determining the length of the SWNTs based upon the specific viscosity by solving, for example, the Kirkwood-Auer equation corrected by Batchelor's formula for the drag on a slender cylinder for “L,” to determine the length of the SWNTs. The apparatus generally comprises: a SWNT sample introduction mechanism; a dispersal chamber; a SWNT radius-determination chamber; and a viscosity determining chamber, wherein the SWNT sample introduction mechanism, the dispersal chamber, the SWNT radius-determination chamber, and the viscosity determination chamber are each operatively connected to at least one of the others.
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    Methods for solubilizing and separating large fullerenes
    (2013-11-26) Rai, Pradeep K.; Parra-Vasquez, Nicholas A. G.; Peng, Haiqing; Hauge, Robert H.; Pasquali, Matteo; Rice University; United States Patent and Trademark Office
    We have discovered that size dependent solubility of large fullerenes in strong acids is dependent on acid strength. This provides a scalable method for separating large fullerenes by size. According to some embodiments, a method for processing a fullerene starting material comprises large fullerenes comprises mixing the starting material with a first concentrated sulfuric acid solution so as to obtain a first dispersion comprising a first portion of the large fullerenes solubilized in the first concentrated sulfuric acid solution.