Examinando por Autor "Martin-Trasanco, R."

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    Ítem
    In-situ preparation of CdTe quantum dots capped with a β-cyclodextrin-epichlorohydrin polymer: Polymer influence on the nanocrystal’s optical properties
    (MDPI AG, 2018-11) Martin-Trasanco, R.; Esparza-Ponce, H.E.; Ortiz, P.D.; Oyarzun, D.P.; Zuñiga, C.; Montero-Cabrera, M.E.; Tundidor-Camba, A.; Pizarro, G.C.; Arratia-Pérez, R.
    β-Cyclodextrin (βCD), the less water soluble of the cyclodextrins, has been used as a capping agent in the preparation of semiconductor nanocrystals or quantum dots (QDs). Nevertheless, no reports have been found in the use of the highly water-soluble polymer of this, prepared by the crosslinking of the βCD units with epichlorohydrin in basic medium (βCDP). This polymer, besides to overcome the low solubility of the βCD, increases the inclusion constant of the guest; two parameters that deserve its use as capping agent, instead of the native cyclodextrin. In the present manuscript, we afforded the in-situ aqueous preparation of cadmium telluride (CdTe) QDs capped with βCDP. The polymer influence on the photoluminescent properties of the nanocrystals was analyzed. The βCDP controls the nanocrystals growth during the Oswald ripening stage. Consequently, the CdTe capped βCDP QDs showed lower Stokes-shift values, higher photoluminescent efficiency, and narrower size distribution than for nanocrystals obtained in the absence of polymer. Transmission electron microscopy (TEM) micrographs and energy dispersive X-ray spectroscopy (EDS) analysis revealed the composition and crystallinity of the CdTe QDs. This βCDP capped CdTe QDs is a potential scaffold for the supramolecular modification of QDs surface. © 2018 by the authors.
  • Miniatura
    Ítem
    Synthesis and morphological characterization of nanocomposite based on anodic TiO2 nanotubes and poly(N-maleoyl Glycine-CO-Acrylic acid)
    (Sociedad Chilena de Quimica, 2017) Oyarzún, D.P.; Pizarro, G.D.C.; Asenjo, A.; Tello, A.; Martin-Trasanco, R.; Zúñiga, C.; Sánchez, J.; Arratia-Perez, R.
    In this study, we examined the synthesis, and characterization of TiO2/poly(N-maleoylglycine-co-acrylic acid) (TiO2/poly(MG-co-AA)) nanocomposite. The nanocomposite was prepared by the dispersion of TiO2 nanotubes in a water solution of the polymer (3% w/w) and then it was lyophilized. The nanocomposite was characterized by FTIR and Raman spectroscopies. The incorporation of TiO2 nanotubes to the polymeric matrix was determined by transmission electron microscopy (TEM) from which TiO2 nanotubes in the inner of copolymer with diameters ranging between 90 and 100 nm were observed. The overall morphology of the previously synthetized nanotubes was determined by scanning electron microscopy (SEM). For the nanocomposite system, the morphology was studied by atomic force microscopy (AFM) from which a grain shape structure was observed. This process resulted in a new nanocompsite material with an average grain diameter estimated by SEM and AFM ranging between 210-240 nm. It was observed that the nanotubes were homogeneously dispersed within the polymeric matrix. The prepared material could be suitable in the design of electronic devices and additionally could have potential applications as biomaterial.