Programas de Investigación

URI permanente para esta comunidadhttps://repositorioinvestigare.pucmm.edu.do/handle/20.500.12060/2096

La PUCMM cuenta con seis (6) programas de investigación e innovación que responden a su misión de buscar soluciones científicas a los desafíos que enfrenta el pueblo dominicano y su entorno global.

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Mostrando 1 - 3 de 3

Carbon nanotubes coated with diamond nanocrystals and silicon carbide by Hot-filament chemical vapor deposition below 200 C substrate temperature
(ELSEVIER) Piazza, Fabrice; Morell, Gerardo; Beltran-Huarac, Juan C.; Paredes, Germercy; Ahmadi, Majid; Guinel, Maxime J.F.
Multi-walled carbon nanotubes (MWCNTs) dispersed onto a silicon substrate have been coated with diamond nanocrystals (DNC) and silicon carbide (SiC) from solid carbon and silicon sources exposed to H2 activated by hot filament chemical vapor deposition (HFCVD) at around 190 °C substrate temperature. MWCNT coating by DNC initiates during filament carburization process at 80 °C substrate temperature under conventional HFCVD conditions. The hybrid nanocarbon material was analyzed by scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, electron energy loss spectroscopy, selected area electron diffraction, X-ray diffraction and Raman spectroscopy. The structure of the MWCNTs is preserved during coating and the smooth DNC/SiC coating is highly conformal. The average grain size is below 10 nm. The growth mechanism of DNC and SiC onto MWCNT surface is discussed.
Synthesis of diamond nanocrystals on polyimide film
(ELSEVIER) Piazza, Fabrice; Solá, Francisco; Resto, Oscar; Fonseca, Luis F.; Morell, Gerardo
Sulfur-assisted hot-filament chemical vapor deposition (HFCVD) was recently employed to grow diamond nano-crystals on polyimide film [F. Piazza, G. Morell, Diamond and Related Materials, 16 (2007) 1950], unambiguously showing that the substrate temperature was below 360 °C, the polyimide glass transition temperature. This accomplishment has opened the door to employ diamond in a wide range of applications where it needs to be integrated with temperature sensitive materials. The result reported earlier relies on visible Raman spectroscopy analysis. We hereby report new additional evidences confirming the result from transmission electron microscopy (TEM), high-resolution TEM, energy dispersive X-ray analysis, electron energy loss spectroscopy and selected area electron diffraction.
Wettability of hydrogenated tetrahedral amorphous carbon
(ELSEVIER) Piazza, Fabrice; Morell, Gerardo
The wettability and surface energy of hydrogenated amorphous carbon films (a-C:H) elaborated by distributed electron cyclotron resonance plasma were studied by contact angle measurements in relation to composition, structure and topography. Tetrahedral a-C:H (ta-C:H) showed relatively high water contact angle (CA) up to 82.3°, and low surface energy (Es), down to 25.3 mJ/m2. Hydrophobicity was found to increase with the intensity of the ion bombardment and with the tetrahedral character. A decrease of the dispersive component is responsible of the decrease of surface energy with substrate bias. Low mass-density polymer-like a-C:H (PLC) presents also a relatively high hydrophobicity with high water CA, up to 76.7°, and low surface energy values, down to 32.1 mJ/m2. Hydrophobicity is interpreted as resulting from a surface layer rich in sp2-carbon for ta-C:H and rich in C–H bonds for PLC.

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Examinando Programas de Investigación por Autor "Morell, Gerardo"