Browsing by Author "Chibante, Luis Paulo Felipe"

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    Oriented nanofibers embedded in a polymer matrix
    (2011-03-01) Barrera, Enrique V.; Rodriguez-Macias, Fernando J.; Lozano, Karen; Chibante, Luis Paulo Felipe; Stewart, David Harris; Rice University; United States Patent and Trademark Office
    A method of forming a composite of embedded nanofibers in a polymer matrix is disclosed. The method includes incorporating nanofibers in a plastic matrix forming agglomerates, and uniformly distributing the nanofibers by exposing the agglomerates to hydrodynamic stresses. The hydrodynamic said stresses force the agglomerates to break apart. In combination or additionally elongational flow is used to achieve small diameters and alignment. A nanofiber reinforced polymer composite system is disclosed. The system includes a plurality of nanofibers that are embedded in polymer matrices in micron size fibers. A method for producing nanotube continuous fibers is disclosed. Nanofibers are fibrils with diameters of 100 nm, multiwall nanotubes, single wall nanotubes and their various functionalized and derivatized forms. The method includes mixing a nanofiber in a polymer; and inducing an orientation of the nanofibers that enables the nanofibers to be used to enhance mechanical, thermal and electrical properties. Orientation is induced by high shear mixing and elongational flow, singly or in combination. The polymer may be removed from said nanofibers, leaving micron size fibers of aligned nanofibers.
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    Production, characterization and reactions of fullerenes
    (1994) Chibante, Luis Paulo Felipe; Smalley, Richard E.
    The new third form of carbon, known collectively as fullerenes, is studied in several general aspects. Efficient production methods have been developed along with an increased understanding into the formation mechanisms. Several physical and chemical properties are investigated in attempts to characterize these unique molecules. An exciting feature of these all-carbon molecules is their ability to undergo chemical modification while maintaining their cage structure, unlike diamond or graphite. One of the fundamental alterations is the addition of oxygen atoms to the cage. Techniques to produce these derivatives and their characterization is also presented.
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    Reaction studies of gallium arsenide clusters: Models of real surfaces
    (1993) Chibante, Luis Paulo Felipe
    As semiconductor technology continues to miniaturize, surface phenomenon become prevalent. Clusters can be considered as model compounds of the surface in free space. By performing experiments on clusters, it is equivalent to focussing on local sites of the bulk surface, and building it one atom at a time. The development of supersonic beams of clusters has proved to be one of the most powerful methods in preparing the "nano" state, the intermediate range between atomic and the macroscopic description of matter. Fourier Transform - Ion Cylcotron Resonance (FT-ICR), a mass spectrometry technique, coupled with these cluster beams was used to study gallium arsenide, a well-utilized semiconductor. The complexity of isomers and the stoichiometric distribution within a given cluster size has been simplified using mathematical methods for signal deconvolution. By studying reaction parameters with ammonia, gallium arsenide clusters proved to be an adequate comparative model for real surfaces. Furthermore, local density theoretical calculations, which are feasible on these small clusters, provided a corroborative and predictive proving ground for this system.