621 research outputs found

    Superhydrophobic supported Ag-NPs@ZnO-nanorods with photoactivity in the visible range

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    In this article we present a new type of 1D nanostructures consisting of supported hollow ZnO nanorods (NRs) decorated with Ag nanoparticles (NPs). The 3D reconstruction by high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM) electron tomography reveals that the Ag NPs are distributed along the hollow interior of the ZnO NRs. Supported and vertically aligned Ag-NPs@ZnO-NRs grow at low temperature (135 °C) by plasma enhanced chemical vapour deposition on heterostructured substrates fabricated by sputtered deposition of silver on flat surfaces of Si wafers, quartz slides or ITO. The growth mechanisms of these structures and their wetting behavior before and after visible light irradiation are critically discussed. The as prepared surfaces are superhydrophobic with water contact angles higher than 150°. These surfaces turn into superhydrophilic with water contact angles lower than 10° after prolonged irradiation under both visible and UV light. The evolution rate of the wetting angle and its dependence on the light characteristics are related to the nanostructure and the presence of silver embedded within the ZnO NRs. ÂEuropean Union NMP3-CT-2006- 032583Ministerio de Ciencia e Innovación MAT2010-21228, MAT2010-18447, CSD2008-00023Junta de Andalucía P09-TEP-5283, CTS-518

    Tratamiento de la imagen corporal en los trastornos de la conducta alimentaria desde la terapia online.

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    La insatisfacción corporal es uno de los factores predisponentes de los trastornos de conducta alimentaria (TCA) y las distorsiones perceptivas del tamaño corporal es un criterio diagnóstico de estos. Actualmente, se han desarrollado intervenciones online para reducir los factores de riesgo de los TCA. El objetivo de este trabajo es llevar a cabo una revisión de la literatura científica sobre el tratamiento de la imagen corporal en los TCA desde la terapia online y poner de manifiesto los avances generados. Se realizó una búsqueda en las bases de datos PsycNET, Scopus y Web of Science. La búsqueda se centró en revisar los programas de intervención para TCA con TIC en el tratamiento de la imagen corporal en TCA. Se encontraron 9 artículos cuyos resultados indican la existencia de diversos programas online como eBody Project, Student Bodies, Set Your Body Free y Healthy Body Image sobre imagen corporal. Los resultados indican, por un lado, que eBody Project y Student Bodies se asocian a una reducción significativa de síntomas de TCA y, por otro lado, Healthy Body Image y Set Your Body Free mostraron mejoras ligeramente significativas en el tratamiento de la imagen corporal para bulimia y trastorno por atracón. La investigación es escasa y presenta muchas limitaciones. Es necesario continuar investigando sobre programas de tratamiento online para la imagen corporal y los TCA ya que el uso de Internet cuenta con múltiples ventajas

    Coarse-grained approach to amorphous and anisotropic materials in kinetic Monte Carlo thin-film growth simulations: A case study of TiO₂ and ZnO by plasma-enhanced chemical vapor deposition

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    The growth of TiO₂ and ZnO thin films is studied by means of coarse-grained kinetic Monte Carlo simulations under conditions typically encountered in plasma-enhanced chemical vapor deposition experiments. The basis of our approach is known to work well to simulate the growth of amorphous materials using cubic grids and is extended here to reproduce not only the morphological characteristics and scaling properties of amorphous TiO₂ but also the growth of polycrystalline ZnO with a good approximation, including the evolution of the film texture during growth and its dependence on experimental conditions. The results of the simulations have been compared with available experimental data obtained by X-ray diffraction, analysis of the texture coefficients, atomic force microscopy, and scanning electron microscopy

    Mechanically switchable wetting petal effect in self‐patterned nanocolumnar films on poly(Dimethylsiloxane)

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    Switchable mechanically induced changes in the wetting behavior of surfaces are of para-mount importance for advanced microfluidic, self‐cleaning and biomedical applications. In this work we show that the well‐known polydimethylsiloxane (PDMS) elastomer develops self‐patterning when it is coated with nanostructured TiO2 films prepared by physical vapor deposition at glancing angles and subsequently subjected to a mechanical deformation. Thus, unlike the disordered wrinkled surfaces typically created by deformation of the bare elastomer, well‐ordered and aligned micro‐scaled grooves form on TiO2/PDMS after the first post‐deposition bending or stretching event. These regularly patterned surfaces can be reversibly modified by mechanical deformation, thereby inducing a switchable and reversible wetting petal effect and the sliding of liquid droplets. When performed in a dynamic way, this mechanical actuation produces a unique capacity of liquid droplets (water and diiodomethane) transport and tweezing, this latter through their selective capture and release depending on their volume and chemical characteristics. Scanning electron and atomic force microscopy studies of the strained samples showed that a dual‐scale rough-ness, a parallel alignment of patterned grooves and their reversible widening upon deformation, are critical factors controlling this singular sliding behavior and the possibility to tailor their response by the appropriate manufacturing of surface structures.European Union 899352Ministerio de Ciencia e Innovación PID2019- 110430GB-C21, PID2019-109603RA-I0, MAT2013-40852-R, MAT2013- 42900-PMinisterio de Economía y Competitividad 201560E055Junta de Andalucía AT17-6079, P18-RT-348

    Optical gas sensing of ammonia and amines based on protonated porphyrin/TiO2 composite thin films

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    Open porous and transparent microcolumnar structures of TiO2 prepared by physical vapour deposition in glancing angle configuration (GLAD-PVD) have been used as host matrices for two different fluorescent cationic porphyrins, 5-(N-methyl 4-pyridyl)-10,15,20-triphenyl porphine chloride (MMPyP) and meso-tetra (N-methyl 4-pyridyl) porphine tetrachloride (TMPyP). The porphyrins have been anchored by electrostatic interactions to the microcolumns by self-assembly through the dip-coating method. These porphyrin/TiO2 composites have been used as gas sensors for ammonia and amines through previous protonation of the porphyrin with HCl followed by subsequent exposure to the basic analyte. UV–vis absorption, emission, and time-resolved spectroscopies have been used to confirm the protonation–deprotonation of the two porphyrins and to follow their spectral changes in the presence of the analytes. The monocationic porphyrin has been found to be more sensible (up to 10 times) than its tetracationic counterpart. This result has been attributed to the different anchoring arrangements of the two porphyrins to the TiO2 surface and their different states of aggregation within the film. Finally, there was an observed decrease of the emission fluorescence intensity in consecutive cycles of exposure and recovery due to the formation of ammonium chloride inside the film.Junta de Andalucía FQM-2310EU-FEDERMinisterio de Economía y Competitividad MAT2013-42900-P MAT2014-57652-C2-2-R MAT2015-69035-REDC MINECO-CSIC 201560E055 PCIN-2015-169-C02-0

    Vacuum template synthesis of multifunctional nanotubes with tailored nanostructured walls

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    A three-step vacuum procedure for the fabrication of vertical TiO2 and ZnO nanotubes with three dimensional walls is presented. The method combines physical vapor deposition of small-molecules, plasma enhanced chemical vapor deposition of inorganic functional thin films and layers and a postannealing process in vacuum in order to remove the organic template. As a result, an ample variety of inorganic nanotubes are made with tunable length, hole dimensions and shapes and tailored wall composition, microstructure, porosity and structure. The fabrication of multishell nanotubes combining different semiconducting oxides and metal nanoparticles is as well explored. This method provides a feasible and reproducible route for the fabrication of high density arrays of vertically alligned nanotubes on processable substrates. The emptying mechanism and microstructure of the nanotubes have been elucidated through SEM, STEM, HAADF-STEM tomography and energy dispersive X-ray spectroscopy. In this article, as a proof of concept, it is presented the straightforward integration of ZnO nanotubes as photoanode in a photovoltaic cell and as a photonic oxygen gas sensorJunta de Andalucia TEP8067 FQM-6900 FQM 1851 P12-FQM-2265España Mineco CONSOLIDER-CSD 2008-00023 MAT2013-40852-R MAT2013-42900-P MAT2013-47192-C3-3-R RECUPERA 2020Unión Europea FP/2007-2013 312483 - ESTEEM2 291522 - 3DIMAGE REGPOT-CT-2011-285895-Al-NANOFUNC

    Anisotropic in-plane conductivity and dichroic gold plasmon resonance in plasma assisted ITO thin films e-beam evaporated at oblique angles

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    ITO thin films have been prepared by electron beam evaporation at oblique angles (OA), directly and while assisting their growth with a downstream plasma. The films microstructure, characterized by scanning electron microscopy, atomic force microscopy and glancing incidence small angle X-ray scattering, consisted of tilted and separated nanostructures. In the plasma 2 assisted films, the tilting angle decreased and the nanocolumns became associated in the form of bundles along the direction perpendicular to the flux of evaporated material. The annealed films presented different in-depth and sheet resistivity as confirmed by scanning conductivity measurements taken for the individual nanocolumns. In addition, for the plasma assisted thin films, two different sheet resistance values were determined by measuring along the nanocolumn bundles or along the perpendicular direction. This in-plane anisotropy induces the electrochemical deposition of elongated gold nanostructures. The obtained Au-ITO composite thin films were characterized by anisotropic plasmon resonance absorption and a dichroic behavior when examined with linearly polarized light

    One-reactor plasma assisted fabrication of ZnO@TiO2 multishell nanotubes: assessing the impact of a full coverage on the photovoltaic performance

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    This paper addresses the fabrication of vertically aligned ZnO@TiO2 multishell nanotubes by a combined full vacuum-plasma approach at mild temperatures. The growth is carried out within the premises of a one-reactor approach, i.e. minimizing the number of vacuum chambers and sample transferences. In this way, the interface between ZnO and TiO2 is fully preserved from humidity thus increasing ZnO durability and stability. These nanostructures are studied by scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM) and energy dispersive X-ray spectroscopy in STEM (EDX-STEM). High density one-dimensional arrays of these nanotubes formed on FTO substrates are applied as photoanode in a dye-sensitized solar cell (DSC). The evolution of the dye adsorption capacity and solar cells parameters are explored as a function of the crystallinity and thickness of the TiO2 shell. The results show the critical effect of a full coverage by TiO2 of ZnO core to explain the mixed results found in the literature.Junta de Andalucia FQM 1851 FQM-2310España Mineco Agencia Estatal de Investigación MAT2016–79866-R MAT2013–42900-P MAT2013– 47192-C3-3-RMINECO-CSIC 201560E055Marie Skłodowska-Curie Actions H2020-MSCA-IF-2014PlasmaPerovSol grant 66148
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