Browsing by Author "Ericson, Lars Martin"

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    Fibers of aligned single-wall carbon nanotubes and process for making the same
    (2006-10-24) Smalley, Richard E.; Saini, Rajesh Kumar; Sivarajan, Ramesh; Hauge, Robert H.; Davis, Virginia Angelica; Pasquali, Matteo; Ericson, Lars Martin; Rice University; United States Patent and Trademark Office
    The present invention involves fibers of highly aligned single-wall carbon nanotubes and a process for making the same. The present invention provides a method for effectively dispersing single-wall carbon nanotubes. The process for dispersing the single-wall carbon nanotubes comprises mixing single-wall carbon nanotubes with 100% sulfuric acid or a superacid, heating and stirring under an inert, oxygen-free environment. The single-wall carbon nanotube/acid mixture is wet spun into a coagulant to form the single-wall carbon nanotube fibers. The fibers are recovered, washed and dried. The single-wall carbon nanotubes were highly aligned in the fibers, as determined by Raman spectroscopy analysis.
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    Macroscopic neat single-wall carbon nanotube fibers
    (2004) Ericson, Lars Martin; Smalley, Richard E.
    Measured and predicted properties of individual single wall carbon nanotubes (SWNT) suggest that bulk SWNT materials will exhibit a variety of exceptional properties. Due to the anisotropic nature of SWNTs, fibers are a logical candidate for these objects. The first ever macroscopic fibers, consisting entirely of SWNTs, were successfully produced and characterized. Nanotubes were dissolved at high concentrations (6--10 wt%) in 102% sulfuric acid. The SWNT/sulfuric acid system exhibited unique one-dimensional liquid crystalline phase behavior and interesting rheological characteristics. Fibers were extruded using a wet jet solution-spinning approach into diethyl ether without extensional drawing. Structural analysis showed them to be the highest aligned neat SWNT material produced to-date, with a revealing substructure of coagulated liquid crystalline domains. Additional characterization showed useful electrical and thermal properties and promising mechanical properties. Finally, the Spinning Bob Mixer (SBM), a custom laboratory mixer/extruder, was designed and successfully tested. Various features of the apparatus were demonstrated and shown to be valuable experimental tools for understanding the production of near SWNT fibers. This research has begun the exploration of an interesting and new field of nanotube science by providing a foundation of understanding and enabling future experiments.
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    Single-wall carbon nanotube alewives- process for making- and compositions thereof
    (2007-10-30) Smalley, Richard E.; Saini, Rajesh Kumar; Sivarajan, Ramesh; Hauge, Robert H.; Davis, Virginia Angelica; Pasquali, Matteo; Ericson, Lars Martin; Kumar, Satish; Veedu, Sreekumar Thaliyil; Rice University; United States Patent and Trademark Office
    The present invention involves alewives of highly aligned single-wall carbon nanotubes (SWNT), process for making the same and compositions thereof. The present invention provides a method for effectively making carbon alewives, which are discrete, acicular-shaped aggregates of aligned single-wall carbon nanotubes and resemble the Atlantic fish of the same name. Single-wall carbon nanotube alewives can be conveniently dispersed in materials such as polymers, ceramics, metals, metal oxides and liquids. The process for preparing the alewives comprises mixing single-wall carbon nanotubes with 100% sulfuric acid or a superacid, heating and stirring, and slowly introducing water into the single-wall carbon nanotube/acid mixture to form the alewives. The alewives can be recovered, washed and dried. The properties of the single-wall carbon nanotubes are retained in the alewives.
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    Strength characterization of suspended single-wall carbon nanotube ropes
    (2001) Ericson, Lars Martin
    Carbon nanotubes are expected to have incredible mechanical properties. Before they can be used intelligently in engineering applications, the capabilities and limitations of these properties must be well understood. This research measured the strain-to-failure of single-wall carbon nanotubes (SWNTs) by elastically straining suspended SWNT ropes using an atomic force microscope in lateral force mode. The ropes experienced multiple scanning cycles at high strains with no plastic deformation. The nanotube ropes were observed to strain as elastic strings, instead of as stiff beams. A maximum strain of 5.9 +/- 0.9% was observed, which led to a lower bound on the yield strength of 45 +/- 7 GPa for single-wall carbon nanotubes. These results are the first experimental evidence that supports the theoretical strain-to-failure of 5% for SWNTs. This research helps to establish single-wall nanotubes as a structural material by further quantifying their mechanical properties.