Browsing by Author "Gómez Costa, Marcos"

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    Composites of polyindole nanowires within silicates and aluminosilicates hosts with distinct conductive properties
    (International Conference on Materials and Engineering Technology, 2015) Juárez, Juliana; Gómez Costa, Marcos; Mugas, Brenda; Anunziata, Oscar
    Nanostructured silicate SBA-15 and aluminosilicate AlSBA-15 were synthesized in order to prepare polyindole composites. The Silica mesoporous materials were prepared by sol–gel method and the alumination by post-synthesis technique, and analyzed by different methods (XRD, BET, TEM, and FTIR). Polyindole/host composites were prepared by an oxidative in situ polymerization of pre-adsorbed indole, em ploying Cl3Fe as oxidant. TG, FTIR, BET, XRD, SEM and TEM were used to characterize the resulting composites. These studies show that after polymerization, the porous structures of the materials are preserved and the Polyindole is found within the porous channels. The composites have an electrical conductivity range between higher than the pure Polyindole chemically synthesized, close to the electrical conductivity of pure polymer electrochemically synthesized, and lower than the pure polymer chemically synthesized, in order of 10-8 S/cm.
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    Encapsulation of PANI nanowires into AI-SBA-3 and AI-SBA-16 nanoporous materials.
    (Univesidsad Tecnológica Nacional, 2011) Gómez Costa, Marcos; Martínez, María; Luna D´Amicis , Froilán; Beltramone, Andrea; Anunziata, Oscar
    The encapsulation of nanosized conducting polymer filaments such as polyaniline, into the channels of mesoporous aluminosilicate hosts (i.e. SBA-3, SBA-16), would permit the feasibility of using mesoporous materials in nanometer-scale for electronic devices. [1, 2]. The goal of this work is to synthesize PANI/Na-AlSBA-3 and PANI/Na-AlSBA-16 composites (with PANI inside of the nanoporous channels of materials), with electrical conducting or semiconducting properties, using in situ polymerization techniques in order to contribute to the understanding of the aniline adsorption mode onto the host and its influence on the final composite material. It could be possible modify conductive properties of composite, varying the substituents of the aromatic ring, the host structure and the anchored sites to adsorb aniline, and the amount of PANI in the hosts.
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    Preparation and characterization of activated CMK-3 modified with vanadium applied in hydrogen storage
    (XXIII INTERNATIONAL MATERIALS RESEARCH CONGRESS, 2014) Juárez, Juliana; Gómez Costa, Marcos; Cussa, Jorgelina; Anunziata, Oscar
    The aim of this work is to synthesize a nanostructured Carbon CMK-3 modified with V in order to increase its capacity in hydrogen storage. The approach that we have followed includes synthesis of nanostructures with the experimental study of its adsorption capacity and storage properties. Ordered nanoporous carbon CMK-3 was synthesized via a two-step impregnation of the SBA-15 mesopores with a solution of sucrose using an incipient wetness method. The sucrose–silica composite was heated at 1173 K for 4 h under nitrogen flow. The silica template was dissolved with 5 wt% hydrofluoric acid in order to remove the silica. The template-free carbon product thus obtained was filtered, washed with deionized water and ethanol, and dried. [1] V-CMK-3 was prepared by wetness impregnation using VCl3 as source of Vanadium in order to increase the amount of hydrogen adsorbed. The sample of V-CMK-3 was treated under H2 flow two times at 1173 K. Porous carbon CMK-3 and the sample modified with V were characterized by XRD, FTIR, XPS, BET, TEM and SEM. These studies indicate that it was possible to obtain a CMK-3 replica successfully from SBA-15, using sucrose as a carbon precursor. [2] The surface areas are 1320 m2/g and 1050 m2/g for CMK-3 and V-CMK-3, respectively. While the nanomaterial area is significantly smaller with the incorporation of the metal, CMK-3`s characteristic structure is maintained after the metal is within the host, in agreement with the XRD studies. Measurements of hydrogen adsorption at cryogenic temperatures and low pressures were performed. The nanoparticles of V incorporated onto the nanostructured carbon CMK-3 showed higher hydrogen uptake at low and high pressures than CMK-3. (3.4 wt% and 2.2 wt% respectively of H2 sorption at 10 bar and 77 K).