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    Two-stage chemical deposition of oxide films

    , Article International Journal of Engineering, Transactions B: Applications ; Volume 21, Issue 1 , 2008 , Pages 65-70 ; 1728-144X (ISSN) Vaezi, M. R ; Sadrnezhaad, S. K ; Sharif University of Technology
    Materials and Energy Research Center  2008
    Two-stage chemical deposition (TSCD) technique is used to produce ZnO, Mn2O3 and NiO films on soda-lime glass (SL-G) from an aqueous solution of zinc, manganese and nickel complex, respectively. The TSCD method enables the deposition of metal oxide thin films with a thickness which can be controlled during the preparation procedure. The ZnO, Mn 2O3 and NiO thin films were polycrystalline films which were adherent well to the substrates. The SEM micrographs clearly indicate that the zinc oxide layer is composed of oval shaped crystallites preferably orientated perpendicular to the surface of the substrate. The Mn 2O3 and NiO layers were closely packed on the substrate. These particles seem to... 

    Dielectric core-shells with enhanced scattering efficiency as back-reflectors in dye sensitized solar cells

    , Article RSC Advances ; Vol. 4, issue. 7 , Oct , 2014 , p. 3621-3626 Ghazyani, N ; Majles Ara M.H ; Tajabadi F ; Dabirian, A ; Mohammadpour, R ; Taghavinia, N ; Sharif University of Technology
    Particulate back-reflector films are conventionally used for the improvement of light harvesting in dye solar cells (DSC). The back-reflection of the films is directly related to the scattering efficiency of the individual particles. Inspired by the idea of multilayer optical thin films, here it is demonstrated theoretically and experimentally that putting a SiO2 shell around spherical rutile-TiO2 particles leads to improved light scattering by the particles. These dielectric core-shells not only enhance the overall diffuse reflection of the films, but they also cause a relative improvement in the red and near infrared regions. Back-reflector films of these core-shell particles employed in... 

    Oxygen-barrier properties of poly(lactic acid)/poly(vinyl acetate-co-vinyl alcohol) blends as biodegradable films

    , Article Journal of Applied Polymer Science ; Volume 125, Issue SUPPL. 2 , September , 2012 , Pages E20-E26 ; 00218995 (ISSN) Razavi, S. M ; Dadbin, S ; Frounchi, M ; Sharif University of Technology
    Wiley  2012
    The oxygen-barrier properties of poly(lactic acid) (PLA)/poly(vinyl acetate-co-vinyl alcohol) [P(VAc-co-VA)] were investigated. P(VAc-co-VA)s with vinyl alcohol (VA) contents of 5, 10, and 15 mol % were prepared with the acid-catalyzed hydrolysis of poly(vinyl acetate). The obtained copolymers with various contents of VA were blended with PLA at 5/95, 10/90, and 15/85 compositions. Films of the blends were prepared by a solution-casting method with chloroform as the cosolvent. Although the blend with 5% VA in the copolymer appeared to be miscible, the blends with 10 and 15% VA content in the copolymer were immiscible, as verified by dynamic mechanical analysis. The oxygen-barrier properties... 

    Synthesis and characterization of electrochemically grown CdSe nanowires with enhanced photoconductivity

    , Article Journal of Materials Science: Materials in Electronics ; Volume 26, Issue 3 , March , 2015 , Pages 1395-1402 ; 09574522 (ISSN) Kalhori, H ; Irajizad, A ; Azarian, A ; Ashiri, R ; Sharif University of Technology
    Springer New York LLC  2015
    CdSe nanowires were grown in polycarbonate track etched membrane with pore diameter of 80 nm by an electrochemical deposition technique. The mechanism of the growth was studied during the potentiostatic deposition of nanowires. X-ray photoelectron spectroscopy and energy dispersive spectrometry results showed binding of fragments and fraction of atoms for the CdSe nanowires. Microstructure and morphology of synthesized CdSe nanowires were observed by scanning electron microscopy. Optical spectrophotometry technique was used to determine the energy band gap of CdSe nanowires. It was found that the nanowires were resistive in the dark and exhibited a pronounced visible light photoconductivity.... 

    Application of glassy carbon electrode modified with a carbon nanoparticle/melamine thin film for voltammetric determination of raloxifene

    , Article Journal of Electroanalytical Chemistry ; Volume 780 , 2016 , Pages 126-133 ; 15726657 (ISSN) Shahrokhian, S ; Ghalkhani, M ; Balotf, H ; Salimian, R ; Sharif University of Technology
    Elsevier B.V  2016
    As a selective estrogen receptor modulator, raloxifene (RXF) prevent of osteoporosis in postmenopausal women by estrogenic actions on bone and decreases the risk of invasive breast cancer by anti-estrogenic actions on the breast and uterus tissue. However, RXF may increase the risk of blood clots, including deep vein thrombosis and pulmonary embolism. For the first time glassy carbon electrode modified with a thin film of melamine/carbon nanoparticles (CNPs/Mela) was constructed and used for the sensitive voltammetric determination of RXF. In comparison with unmodified electrode, the presence of the CNPs/Mela film resulted in a remarkable increase in the peak currents and sharpness of the... 

    Characterization of optical properties of amorphous BaTiO3 nanothin films

    , Article Journal of Non-Crystalline Solids ; Volume 355, Issue 50-51 , 2009 , Pages 2480-2484 ; 00223093 (ISSN) Ashiri, R ; Nemati, A ; Sasani Ghamsari, M ; Aadelkhani, H ; Sharif University of Technology
    Amorphous barium titanate nanothin films were prepared by sol-gel dip-coating method. According to transmission spectrum, the refractive index and optical band gap of nanothin films have been determined. High transmission spectrum without any fluctuation in visible wavelength region was recorded. Experimental results indicated that the surface morphology of prepared nanothin films were improved and as a result of that, a better optical properties, less optical losses and higher band gap width were obtained in contrast with other reported data. It was found that optical propagation loss of BaTiO3 nanothin film was much lower than normal polycrystalline BaTiO3 thin film. It seems to us that,... 

    Poly (vinyl alcohol)/nano-diamond composite films and hydrogels prepared by gamma ray

    , Article Journal of Polymer Engineering ; Volume 38, Issue 9 , 2018 , Pages 857-862 ; 03346447 (ISSN) Frounchi, M ; Dadbin, S ; Haddadi, S ; Sharif University of Technology
    De Gruyter  2018
    Poly (vinyl alcohol) and nano-diamond, PVA/ND, hydrogels were prepared and assessed as prosthetic material suitable for replacement of the nucleus pulposus. The hydrogels were prepared by gamma irradiation at various doses (15 kGy, 25 kGy, 35 kGy, 45 kGy) and at various ND concentrations ranging from 0.25 wt.% to 3 wt.%. Extent of gelation, equilibrium water content, and viscoelastic properties of swelled hydrogels at definite water contents were measured and examined as a function of ND concentration as well as gamma dose. According to viscoelastic measurements, the strength of hydrogels increased considerably over that of pure PVA at a low concentration of ND. By increasing irradiation... 

    TPU/graphene nanocomposites: effect of graphene functionality on the morphology of separated hard domains in thermoplastic polyurethane

    , Article Polymer ; Volume 148 , 18 July , 2018 , Pages 169-180 ; 00323861 (ISSN) Razeghi, M ; Pircheraghi, G ; Sharif University of Technology
    Elsevier Ltd  2018
    Graphene nanoplatelets with different surface functional groups and polarity were prepared by Hummer's method and electrochemical exfoliation of graphite in two aqueous acids. The XRD, FTIR and sedimentation tests performed to characterize the polarity of the prepared graphenes. The highest polarity was associated with the sample prepared by Hummer's method and the sample synthesized by electrochemical exfoliation in nitric acid medium showed the moderate polarity. Meanwhile, the sample prepared in sulfuric acid medium showed the lowest polarity. Then thermoplastic polyurethane (TPU)/graphene nanocomposite films were fabricated with solvent exchange method. While the dispersion state and... 

    Poly (vinyl alcohol)/graphene oxide nanocomposite films and hydrogels prepared by gamma ray

    , Article Plastics, Rubber and Composites ; Volume 48, Issue 2 , 2019 , Pages 42-47 ; 14658011 (ISSN) Frounchi, M ; Dadbin, S ; Tabatabaei, M ; Sharif University of Technology
    Taylor and Francis Ltd  2019
    Poly (vinyl alcohol)/graphene oxide (PVA/GO) gamma irradiated nanocomposite films and hydrogels were prepared. In composite films, GO was initially irradiated by gamma ray in order to improve interactions between GO and PVA. The film containing 1 wt-% GO was very strong where tensile modulus and tensile yield strength were 45 and 115% higher than those of pure PVA. In the second set of experiments PVA/GO hydrogels were made by irradiating PVA/GO suspensions by gamma ray at various doses. It was an interesting finding that GO increased the gel portion of hydrogels through contribution of H-bonds between PVA and GO. The hydrogels prepared at 20 kGy had remarkable water swelling ratio that... 

    Preparation and characterization of poly-lactic acid based films containing propolis ethanolic extract to be used in dry meat sausage packaging

    , Article Journal of Food Science and Technology ; Volume 57, Issue 4 , 2020 , Pages 1242-1250 Safaei, M ; Roosta Azad, R ; Sharif University of Technology
    Springer  2020
    In this study, active poly lactic acid (PLA) films containing 0, 10, 20 and 40% w/w propolis extract (PE), as active agent, were developed. A high amount of phenolic content (PC) was measured in PE. The antioxidant effect of active PLA films was determined by measuring the PC of sausage slices after 0, 2 and 4 days storage at refrigerator. Results showed that phenolic compounds of PE were released from PLA films in quantities proportional to PE concentration. Disc diffusion test indicated that PE showed an inhibitory effect against Staphylococcus aureus and Pseudomonas aeruginosa bacterial species but was more effective against gram-positive species. PE containing PLA films had antimicrobial... 

    Thermal Hall and Nernst responses in ultrathin magnetic films of pyrochlore lattice

    , Article Journal of Physics Condensed Matter ; Volume 33, Issue 26 , 2021 ; 09538984 (ISSN) Sheikhi, B ; Kargarian, M ; Langari, A ; Sharif University of Technology
    IOP Publishing Ltd  2021
    The ultrathin films of pyrochlore lattice along [111] direction provide a fertile ground for exploring topological states in oxide materials, where the electron correlations are strong and magnetically ordered states are favored. As a result of strong interactions, most of states are magnetic insulators with strong Dzyaloshinskii–Moriya and anisotropic spin interactions. We considered three types of heterostructures, a bilayer of triangular-kagome (TK), and two trilayers of triangular-kagome-triangular (TKT) and kagome-triangular-kagome (KTK) thin films. The ground states are magnetically ordered with the low-energy excitations, the magnons, characterized by nontrivial topology. While for TK... 

    Crack-free nanostructured BaTiO3 thin films prepared by sol-gel dip-coating technique

    , Article Ceramics International ; Vol. 40, issue. 6 , 2014 , pp. 8613-8619 Ashiri, R ; Nemati, A ; Sasani Ghamsari, M ; Sharif University of Technology
    In this report, crack-free nanostructured barium titanate thin films are prepared by a sol-gel processing method. Glacial acetic acid, barium acetate, titanium tetraisopropyl alkoxide, 2-propanol and deionized water are used as precursors for preparing stable precursor solution. Then very thin films (thickness=26 nm) are deposited on fused silica substrates. In order to prepare crack-free thin films of BaTiO3, much attention is given to solvent evaporation process and a controlled pre-drying process is developed. It is found that the control of the process, especially in the initial stage of drying process is crucial and important for preparation of the crack-free ultrathin nanostructured... 

    Nickel hydroxide nanoparticles-reduced graphene oxide nanosheets film: Layer-by-layer electrochemical preparation, characterization and rifampicin sensory application

    , Article Talanta ; Vol. 119 , 2014 , pp. 156-163 ; ISSN: 00399140 Rastgar, S ; Shahrokhian, S ; Sharif University of Technology
    Electrochemical deposition, as a well-controlled synthesis procedure, has been used for subsequently layer-by-layer preparation of nickel hydroxide nanoparticle-reduced graphene oxide nanosheets (Ni(OH)2-RGO) on a graphene oxide (GO) film pre-cast on a glassy carbon electrode surface. The surface morphology and nature of the nano-hybrid film (Ni(OH)2-RGO) was thoroughly characterized by scanning electron and atomic force microscopy, spectroscopy and electrochemical techniques. The modified electrode appeared as an effective electro-catalytic model for analysis of rifampicin (RIF) by using linear sweep voltammetry (LSV). The prepared modified electrode exhibited a distinctly higher activity... 

    Synthesis of highly pure nanocrystalline and mesoporous CaTiO3 by a particulate sol-gel route at the low temperature

    , Article Journal of Sol-Gel Science and Technology ; Volume 68, Issue 2 , 2013 , Pages 324-333 ; 09280707 (ISSN) Mohammadi, M. R ; Fray, D. J ; Sharif University of Technology
    The low temperature perovskite-type calcium titanate (CaTiO3) thin films and powders with nanocrystalline and mesoporous structure were prepared by a straightforward particulate sol-gel route. The prepared sol had a narrow particle size distribution about 17 nm. X-ray diffraction and Fourier transform infrared spectroscopy revealed that, the synthesized powders had highly pure and crystallized CaTiO3 structure with preferable orientation growth along (1 2 1) direction at 400-800 °C. The activation energy of crystal growth was calculated 5.73 kJ/mol. Furthermore, transmission electron microscope images showed that the average crystallite size of the powders annealed at 400 °C was around 3.5... 

    CO gas sensor properties of Cu@CuO core-shell nanoparticles based on localized surface plasmon resonance

    , Article Journal of Physical Chemistry C ; Volume 115, Issue 45 , 2011 , Pages 22126-22130 ; 19327447 (ISSN) Ghodselahi, T ; Zahrabi, H ; Saani, M. H ; Vesaghi, M. A ; Sharif University of Technology
    Hexagonal array of Cu@CuO core-shell nanoparticles (NPs) on the a-C:H thin film was prepared by codeposition of RF-sputtering and RF-PECVD. The trace of hexagonal NPs supperlattice was recognized by AFM image and XRD result. On the basis of localized surface plasmon resonance (LSPR) of core-shell NPs, the prepared array detected a low flow rate of CO gas at room temperature. XPS results indicate that the surface of Cu@CuO core-shell NPs have no chemical reaction with CO molecule. The physical absorption of CO molecule on the surface of Cu@CuO core-shell NPs increases the LSPR absorbance and causes a red shift in LSPR wavelength. These experimental results are in agreement with Mie theory... 

    Effects of tin valence on microstructure, optical, and electrical properties of ITO thin films prepared by sol–gel method

    , Article Journal of Sol-Gel Science and Technology ; Volume 75, Issue 3 , September , 2015 , Pages 582-592 ; 09280707 (ISSN) Mirzaee, M ; Dolati, A ; Sharif University of Technology
    Kluwer Academic Publishers  2015
    Abstract: This study aimed to understand the microstructural, optical, and electrical properties of tin-doped indium oxide (ITO) prepared with tetravalent and divalent tin salts. The influence of tin valence on the electrical, optical, structural, and morphological properties of the films were characterized by the mean of four-point probe, thermogravimetric analysis, differential thermal analysis (DTA), UV–Vis spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and X-ray photoelectron spectroscope. XRD results revealed formation of cubic bixbyite structure of In2O3 with a small shift in major peak position toward lower angles with... 

    Preparation and Properties of Ethylene-vinyl Acetate/linear Low-density Polyethylene/Graphene Oxide Nanocomposite Films

    , Article Polymer - Plastics Technology and Engineering ; Volume 54, Issue 11 , 2015 , Pages 1152-1158 ; 03602559 (ISSN) Bahmanyar, M ; Ramazani, S. A ; Baniasadi, H ; Sharif University of Technology
    Taylor and Francis Inc  2015
    Ethylene-vinyl acetate-based nanocomposites with 18 and 28 wt% vinyl acetate were prepared via solution casting method. To improve the mechanical and barrier properties of ethylene-vinyl acetate, linear low-density polyethylene, and graphene oxide were introduced to matrix. The morphological studies indicated that the graphene oxide diffraction peak disappeared in all prepared nanocomposites, probably due to its exfoliation; also proper dispersion and good interaction between nanofillers and polymer matrix were achieved. By introducing low amount of graphene oxide into the matrix, the mechanical and thermal properties and oxygen permeability were improved especially for those with 28 wt%... 

    Development of block copolymer-templated crack-free mesoporous anatase-TiO2 film: tailoring sol–gel and EISA processing parameters and photovoltaic characteristics

    , Article Journal of Materials Science: Materials in Electronics ; Volume 26, Issue 3 , March , 2015 , Pages 1543-1553 ; 09574522 (ISSN) Mozaffari, N ; Mohammadi, M. R ; Faghihi Sani, M. A ; Sharif University of Technology
    Springer New York LLC  2015
    A new facile strategy for preparation of mesoporous anatase-TiO2 films by a combination of sol–gel and evaporation-induced self-assembly (EISA) processes aided by tri-block Pluronic F127 is reported. Two major parameters, sol preparation and EISA processing parameters, are identified for preparation of mesoporous crack-free films with desired thickness. The mesoporous crack-free films with thickness of 650 nm can be obtained with low water: precursor molar ratio (e.g., 2.5:1) under aging in 10 % relative humidity for 72 h at the low temperature of 5 °C. Although template: precursor molar ratio and annealing temperature show little influence on preparation of crack-free films the optimum... 

    Preparation of PVA nanocomposites using salep-reduced graphene oxide with enhanced mechanical and biological properties

    , Article RSC Advances ; Volume 5, Issue 112 , 2015 , Pages 92428-92437 ; 20462069 (ISSN) Pourjavadi, A ; Pourbadiei, B ; Doroudian, M ; Azari, S ; Sharif University of Technology
    Royal Society of Chemistry  2015
    Salep, known as a biodegradable polysaccharide, is hydrolyzed and used as both a reducing agent and stabilizer for graphene oxide (GO). The functionalized reduced graphene oxide (f-rGO) is homogenously dispersed in an aqueous solution of poly(vinyl alcohol) (PVA). PVA based hydrogel and film nanocomposites are prepared and proposed as new biomaterials for tissue engineering applications. The mechanical properties of the film nanocomposites are investigated with varying content of f-rGO, glycerol and citric acid as a reinforcing agent, a plasticizer agent and a cross linking agent respectively. For the first time, chemically cross linked PVA hydrogels are synthesized using... 

    Preparation of ethylene vinyl acetate copolymer/graphene oxide nanocomposite films via solution casting method and determination of the mechanical properties

    , Article Polymer - Plastics Technology and Engineering ; Volume 54, Issue 2 , Jan , 2015 , Pages 218-222 ; 03602559 (ISSN) Bahmanyar, M ; Sedaghat, S ; Ramazani S. A, A ; Baniasadi, H ; Sharif University of Technology
    Taylor and Francis Inc  2015
    Ethylene vinyl acetate/graphene oxide (EVA/GO) nanocomposite films were prepared via solution casting method. The morphological studies investigated using SEM and XRD methods and the results confirmed the formation of likely exfoliation structures and good interaction between matrix and fillers. The results of permeability measurements showed that films have good resistance against oxygen. Mechanical measurements revealed that Young’s modulus and tensile strength of EVA have improved with introducing GO because of proper dispersion of GO into matrix and good interaction between them; however, elongation at break decreased due to formation of strong and rigid polymer/filler network preventing...