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    Flower-like boehmite nanostructure formation in two-steps

    , Article Journal of Coordination Chemistry ; Volume 67, Issue 3 , 1 February , 2014 , Pages 555-562 ; ISSN: 00958972 Zanganeh, N ; Zanganeh, S ; Rajabi, A ; Allahkarami, M ; Rahbari Ghahnavyeh, R ; Moghaddas, A ; Aieneravaie, M ; Asadizanjani, N ; Sadrnezhaad, S. K ; Sharif University of Technology
    Abstract
    Reaction between AlCl3 and TEA (triethanolamine) gave Al(OH)3 colloidal nanocrystals that were precursors to nucleation and growth of boehmite under hydrothermal conditions. Transition electron microscopic (TEM) observations revealed that flower-like nanostructures were produced through a binary self-assembly system. In the first stage, nanostrips organize themselves to form a bundle, because of NH4 + and TEA. In the second stage, the bundles form flower-like nanostructures due to the interaction of nitrate with TEA. The size of the nanopetals (length 100-200 nm; width 100-150 nm; and thickness 20-70 nm) was measured through TEM. X-ray diffraction and Brunauer-Emmett-Teller (BET-N2) results... 

    Fabrication and applications of self-assembled nanopillars

    , Article AIMS Materials Science ; Volume 4, Issue 4 , 2017 , Pages 905-919 ; 23720484 (ISSN) Ji, H. F ; Samadi, M ; Gu, H ; Tomchak, V ; Qiao, Z ; Sharif University of Technology
    AIMS Press  2017
    Abstract
    In this mini-review, we summarize fabrication methods, formation mechanisms, factors that control the characteristics, and applications of self-assembled nanopillars. Nanopillars prepared both in the gas phase and in solutions are discussed. © 2017 Hai-Feng Ji, et al  

    Nanoparticulate hollow TiO 2 fibers as light scatterers in dye-sensitized solar cells: Layer-by-layer self-assembly parameters and mechanism

    , Article ChemPhysChem ; Volume 12, Issue 5 , 2011 , Pages 966-973 ; 14394235 (ISSN) Rahman, M ; Tajabadi, F ; Shooshtari, L ; Taghavinia, N ; Sharif University of Technology
    Abstract
    Hollow structures show both light scattering and light trapping, which makes them promising for dye-sensitized solar cell (DSSC) applications. In this work, nanoparticulate hollow TiO 2 fibers are prepared by layer-by-layer (LbL) self-assembly deposition of TiO 2 nanoparticles on natural cellulose fibers as template, followed by thermal removal of the template. The effect of LbL parameters such as the type and molecular weight of polyelectrolyte, number of dip cycles, and the TiO 2 dispersion (amorphous or crystalline sol) are investigated. LbL deposition with weak polyelectrolytes (polyethylenimine, PEI) gives greater nanoparticle deposition yield compared to strong polyelectrolytes... 

    Graphene-mediated self-assembly of gold nanorods into long fibers with controllable optical properties

    , Article Materials Letters ; Volume 224 , 2018 , Pages 13-17 ; 0167577X (ISSN) Bagheri, P ; Farivar, M ; Simchi, A ; Sharif University of Technology
    Elsevier B.V  2018
    Abstract
    The paper presents graphene-templated self-assembly of gold nanorods into long fibers with controllable optical properties. It is shown that the size of self-assembled nanostructures varies with time and is controlled by chemical reactions between amine groups of graphene and the functional groups of gold. The absorption peak of the nanostructures changes over time while the photoluminescence intensity is quenched. The self-assembled nanostructures with variable plasmon resonance effects are potentially usable for the fabrication of nanoscale devices for biomedical applications. © 2018 Elsevier B.V  

    Supramolecular self-assembly of oleylamide into organogels and hydrogels: a simple approach in phase selective gelation of oil spills

    , Article Soft Materials ; Volume 18, Issue 1 , 2020 , Pages 55-66 Eftekhari Sis, B ; Bagheri, A ; Younesi Araghi, H ; Akbari, A ; F. Paige, M ; Sharif University of Technology
    Taylor and Francis Inc  2020
    Abstract
    A new gelator based of oleylamide has been introduced, which was gelled nonpolar hydrocarbon and CCl4 solvents through self-assembly. Also, the gelator formed a two-component hydrogel in combination with SDS, an anionic surfactant. UV-Vis studies revealed that the H-type and J-type aggregation of organogels in hexane and hydrogel in water, respectively. The xerogel, obtained by evaporating the solvent of organogel, selectively gelled and adsorbed oil spills on water surfaces. The effect of the various parameters, including temperature, water acidity and pH on the oil spill adsorption was studied, revealing the high ability of the xerogel to removing the oil contamination from water in up to... 

    Selfassembled, nanowire network electrodes for depleted bulk heterojunction solar cells (Adv. Mater. 12/2013) [electronic resource]

    , Article Journal of Advanced Materials ; March 2013, Vol. 25, Issue 12, PP. 1768 Lan, X. (Xinzheng) ; Bai, Jing ; Masala, Silvia ; Thon, Susanna M ; Ren, Yuan ; Kramer, Illan J ; Hoogland, Sjoerd ; Simchi, A. (Abdolreza) ; Koleilat, Ghada I ; Paz‐Soldan, Daniel ; Ning, Zhijun ; Labelle, André J ; Kim, Jin Young ; Jabbour, Ghassan ; Sargent, Edward H ; Sharif University of Technology
    Abstract
    A solution-processed, bottom-up nanowire network electrode is developed and employed in a bulk heterojunction colloidal quantum dot solar cell. The electrode features a ZnO template which is converted into locally connected, infi ltratable TiO2 nanowires. The new electrode allows the application of a thicker light absorbing fi lm without compromising the charge extraction, as reported by Edward H. Sargent, Ghassan Jabbour, and co-workers on page 1769. The frontispiece shows schematically the electrode shape and the resultant device architecture  

    Gold electrode modified with self-assembled monolayer of cysteamine-functionalized mwcnt and its application in simultaneous determination of dopamine and uric acid

    , Article Electroanalysis ; Volume 24, Issue 2 , February , 2012 , Pages 425-432 ; 10400397 (ISSN) Shahrokhian, S ; Mahdavi Shakib, A ; Ghalkhani, M ; Saberi, R. S ; Sharif University of Technology
    Abstract
    The voltammetric behavior of dopamine (DA) and uric acid (UA) on a gold electrode modified with self-assembled monolayer (SAM) of cysteamine (CA) conjugated with functionalized multiwalled carbon nanotubes (MWCNTs) was investigated. The film modifier of functionalized SAM was characterized by means of scanning electron microscopy (SEM) and also, electrochemical impedance spectroscopy (EIS) using para-hydroquinone (PHQ) as a redox probe. For the binary mixture of DA and UA, the voltammetric signals of these two compounds can be well separated from each other, allowing simultaneous determination of DA and UA. The effect of various experimental parameters on the voltammetric responses of DA and... 

    Chemically bonded carbon nanotubes on modified gold substrate as novel unbreakable solid phase microextraction fiber

    , Article Microchimica Acta ; Volume 174, Issue 3 , September , 2011 , Pages 295-301 ; 00263672 (ISSN) Bagheri, H ; Ayazi, Z ; Sistani, H ; Sharif University of Technology
    2011
    Abstract
    A new technique is introduced for preparation of an unbreakable fiber using gold wire as a substrate for solid phase microextraction (SPME). A gold wire is used as a solid support, onto which a first film is deposited that consists of a two-dimensional polymer obtained by hydrolysis of a self-assembled monolayer of 3-(trimethoxysilyl)-1-propanthiol. This first film is covered with a layer of 3-(triethoxysilyl)-propylamine. Next, a stationary phase of oxidized multi-walled carbon nanotubes was chemically bound to the surface. The synthetic strategy was verified by Fourier transform infrared spectroscopy and scanning electron microscopy. Thermal stability of new fiber was examined by... 

    Morphology modification of the iron fumarate MIL-88A metal–organic framework using formic acid and acetic acid as modulators

    , Article European Journal of Inorganic Chemistry ; Volume 2018, Issue 18 , 2018 , Pages 1909-1915 ; 14341948 (ISSN) Bagherzadeh, E ; Zebarjad, S. M ; Madaah Hosseini, H. R ; Sharif University of Technology
    Wiley-VCH Verlag  2018
    Abstract
    Metal–organic frameworks (MOFs) are best known for their great structural diversity. The uniformity in the properties of MOFs is mainly governed by the size and morphology of the particles. In the present research, iron-MIL-88A was prepared by a modulator-assisted solvothermal method, and the role of modulating agents in the formation process of MOF particles was investigated. Acetic acid and formic acid were chosen as monoligand modulating agents. The changes in morphology and size distribution of the products were scrutinized by using SEM micrographs. Both modulators clearly interfered with the crystallization process through their attachment to the reactive sites. At low modulator... 

    Fabrication of self-organized precisely tunable plasmonic SERS substrates via glancing angle deposition

    , Article Physica Status Solidi (A) Applications and Materials Science ; Volume 214, Issue 9 , 2017 ; 18626300 (ISSN) Rezvani, E ; Ualibek, O ; Bulfin, B ; Sugurbekova, G ; Duesberg, G. S ; Shvets, I ; Sharif University of Technology
    Abstract
    Plasmonic nanostructures offer great enhancement of the Raman signal due to the strong confinement of the electromagnetic field. Thus, they are considered as suitable candidates for surface enhanced Raman spectroscopy (SERS). In this work, we present an alternative fabrication route, called the glancing angle deposition (GLAD), for tunable fabrication of plasmonic self-organized Ag nanoparticle arrays aimed at SERS. Using the GLAD technique, the inter-particle distance within the arrays can be made as small as 1 nm. Moreover, the plasmonic resonance can be precisely tuned over the whole visible range. The GLAD method can be up-scaled; and when a transparent substrate is used, it enables... 

    Self-Assembly of Colloidal Particles in Liquid Crystal

    , Ph.D. Dissertation Sharif University of Technology Eskandari, Zahra (Author) ; Ejtehadi, Mohammad Reza (Supervisor) ; Telo da Gama, Margarida (Co-Advisor)
    Abstract
    A nematic colloid is a mixture of microscopic particles dispersed in a nematic liquid crystal (NLC), which is an anisotropic fluid with long-range orientational order. This long-range order might be perturbed due to different reasons, such as confinement between flat or curved surfaces which leads to frustration of the nematic director in some singular points or lines called ”topological defects”. The nucleation and the structure of these defects emerge from the elastic properties of NLC and leads to unique behavior of nematic colloids. The interaction between colloidal particles in simple fluids are mainly excluded volume interactions, electrostatic interactions, van der Waals interactions,... 

    Rapid and simultaneous determination of tetracycline and cefixime antibiotics by mean of gold nanoparticles-screen printed gold electrode and chemometrics tools

    , Article Measurement: Journal of the International Measurement Confederation ; Vol. 47, Issue. 1 , 2014 , pp. 145-149 ; ISSN: 02632241 Asadollahi-Baboli, M ; Mani-Varnosfaderani, A ; Sharif University of Technology
    Abstract
    The screen-printed gold electrode (SPGE) modified with the formation of self-assembly monolayer (SAM) of cysteine (Cys) on gold-nanoparticles (Au nano) was utilized for rapid and simultaneous determination of tetracycline and cefixime antibiotics by square wave voltammetry (SWV). Electrochemical investigation and characterization of the modified electrode was achieved using cyclic voltammetry (CV) and scanning electron microscopy (SEM). A principal component artificial neural network (PCANN) with three layer back-propagation network was utilized for the analysis of the voltammogram data. It is possible to simultaneously determine the tetracycline and cefixime concentrations in the ranges of... 

    Nanostructured TiO2 thick films aided by new viscous gels for dye-sensitized solar cell applications

    , Article Journal of Sol-Gel Science and Technology ; Volume 82, Issue 2 , 2017 , Pages 541-550 ; 09280707 (ISSN) Babamahdi, Z ; Mohammadi, M. R ; Sharif University of Technology
    Springer New York LLC  2017
    Abstract
    We develop a facile route for deposition of mesoporous TiO2 thick films over several micrometers by sol–gel and evaporation-induced self-assembly processes using Pluronic F127. The light harvesting of deposited films by two different methods (i.e., using a viscous gel and a paste) is studied by controlling their mesoscopic characteristics, phase composition and thickness for dye-sensitized solar cells applications. It is revealed that the mesoscopic films have mixtures of anatase and rutile crystal structures with surface area in the range 50.6–94.6 m2/g. We observe that the mesoporous TiO2 films prepared under optimized conditions improve light harvesting and dye loading of photoelectrodes.... 

    Effect of Cysteine Substitutions on the Structural and Magnetic Properties of Fe3O4–Cysteine/RGO and Fe3O4/RGO–Cysteine Nanocomposites

    , Article Journal of Superconductivity and Novel Magnetism ; 2018 ; 15571939 (ISSN) Sahebalzamani, H ; Mehrani, K ; Madaah Hosseini, H. R ; Zare, K ; Sharif University of Technology
    Springer New York LLC  2018
    Abstract
    We synthesized by electrostatic self-assembly route in basic solution Fe3O4–cysteine/RGO and Fe3O4/RGO–cysteine nanocomposites. In this method, electrostatic interaction was created via negatively charged surface of the reduced graphene oxide and reduced graphene oxide–cysteine sheets and positively charged surface of the Fe3O4 and Fe3O4–Cys nanoparticles in aqueous solution. The structural and magnetic properties of the prepared samples were analyzed by x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, transmission electron microscopy (TEM), and vibrating sample magnetometer (VSM), respectively. The dependences of magnetization as a function of... 

    Self-assembly of tryptophan-capped gold nanoparticles onto DNA network template

    , Article Journal of Dispersion Science and Technology ; Volume 30, Issue 2 , 2009 , Pages 254-258 ; 01932691 (ISSN) Sheikholeslami, Z ; Vosoughi, M ; Alemsadeh, I ; Sharif University of Technology
    2009
    Abstract
    In this study, a simple route to the formation of DNA-gold complex has been reported, using immobilized DNA as a template. The nanoporous gold films have been prepared by the electrostatic self assembly of gold nanoparticles capped with tryptophan. Tryptophan would improve surface properties of gold nanoparticles for strongly attaching to DNA. Fourier transform infrared spectroscopy confirmed that gold nanoparticles have been capped by tryptophan. Also measured zeta potential shows that there are positive charges on the surface of gold nanoparticles. Investigations by atomic force microscopy substantially confirm that tryptophan-capped gold nanoparticles can be bonded to DNA template... 

    Fabrication of metal nanowires based on self assembly of tryptophan-capped gold nanoparticle onto DNA network template

    , Article International Journal of Nanotechnology ; Volume 6, Issue 10-11 , 2009 , Pages 1041-1049 ; 14757435 (ISSN) Sheikholeslami, Z ; Vossoughi, M ; Alemzadeh, I ; Sharif University of Technology
    2009
    Abstract
    In this study, synthesis of conductive metal nanowires by using aligned and immobilised DNA strand on solid substrate is reported. The nanoporous gold film was prepared by electrostatic self assembly of gold nanoparticles capped with tryptophan. Tryptophan would improve surface properties of gold nanoparticles for strongly attaching to DNA. Fourier transform infrared (FTIR) spectroscopy confirmed that gold nanoparticles have been capped by tryptophan. Also measured zeta potential shows that there are positive charges on the surface of gold nanoparticles. Investigations by AFM observati on substantially confirm that tryptophan-capped gold nanoparticles can be bonded to DNA template... 

    Effect of cysteine substitutions on the structural and magnetic properties of Fe3O4–Cysteine/RGO and Fe3O4/RGO–Cysteine nanocomposites

    , Article Journal of Superconductivity and Novel Magnetism ; Volume 32, Issue 5 , 2019 , Pages 1299-1306 ; 15571939 (ISSN) Sahebalzamani, H ; Mehrani, K ; Madaah Hosseini , H. R ; Zare, K ; Sharif University of Technology
    Springer New York LLC  2019
    Abstract
    We synthesized by electrostatic self-assembly route in basic solution Fe3O4–cysteine/RGO and Fe3O4/RGO–cysteine nanocomposites. In this method, electrostatic interaction was created via negatively charged surface of the reduced graphene oxide and reduced graphene oxide–cysteine sheets and positively charged surface of the Fe3O4 and Fe3O4–Cys nanoparticles in aqueous solution. The structural and magnetic properties of the prepared samples were analyzed by x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, transmission electron microscopy (TEM), and vibrating sample magnetometer (VSM), respectively. The dependences of magnetization as a function of... 

    Synthesis and Study of Electron Transport through a Self-Assembled Monolayer of Thiol-End-Functionalized Tetraphenylporphyrines and Metalo-Tetraphenylporphyrines and Electrochemical Analysis of Dopamine and Ascorbic Acid with this SAMs

    , M.Sc. Thesis Sharif University of Technology Sanaei, Mahsa (Author) ; Mohammadi Boghaei, Davar (Supervisor)
    Abstract
    Self-Assembled Monolayer (SAM) is the first step in all surface engineering and assembly processes. It is used in sensor fabrication, memories and molecular recognition and optoelectronic devises as an active surface for patterning and chemical architecting of solid substrates. Tetraphenyl porphyrins because of their high stability and uniqe electronic and optic properties, that comes from their conjugate π electrons, easily can be used in these monolayers. Moreover they have a wide application because of their ability for coordination with metals and accepting substituents with electron donating and withdrawing properties. Electron transport through these layars which attach to the surface... 

    Synthesis and Characterization of Nano-Composite Based on Supramolecuylar Poly Caprolactone/ Hydroxyapatite for Tissue Engineering Application

    , M.Sc. Thesis Sharif University of Technology Mehmanchi, Mohammad (Author) ; Bagheri, Reza (Supervisor) ; Shokrollahi, Parvin (Supervisor) ; Ataei, Mohammad (Co-Advisor)
    Abstract
    Synthetic polymers have a high capacity to provide and manufacture the pieces used in tissue engineering. However, optimizing the biocompatibility, bioresorbableility and mechanical properties simultaneous with processability of material is complicated and requires a lot of effort at designing different parts of the system. On the other hand, due to existence of secondary bonds (such as metal-ligand coordination or hydrogen bond) supramolecular polymers are able to respond to some stimuli such as temperature, pH, or pressure, which is important in terms of dynamic nature of interaction between the living cells and the external matrix of cell. Recently there have been extensive studies on... 

    Design and Construction of Two-Wheeled Mobile Robot Platform with the Ability to Connect to other Robots with Two Rotational Degrees of Freedom

    , M.Sc. Thesis Sharif University of Technology Golmirzaei, Ali (Author) ; Sayyaadi, Hassan (Supervisor)
    Abstract
    Due to the advantages of multi-agent systems, research in this area and the use of these systems in industry are increasingly growing. Applying these robots, various complex tasks can be done faster, safer and with better results. In our country, many different algorithms have been proposed and simulated, but due to the lack of a real environment for implementation, their actual performance has not been assessed. This project aims to create a platform for research and development of this field. This goal is achieved by performing the first phase of implementation, namely the design and construction of the robot platform. In the first step, qualitative and quantitative characteristics of the...