Search for: coatings
Total 639 records
An aniline-based fiber coating for solid phase microextraction of polycyclic aromatic hydrocarbons from water followed by gas chromatography-mass spectrometry, Article Journal of Chromatography A ; Volume 1152, Issue 1-2 , 2007 , Pages 168-174 ; 00219673 (ISSN) ; Babanezhad, E ; Eshaghi, A ; Sharif University of Technology
A fiber coating from polyaniline (PANI) was electrochemically prepared and employed for solid phase microextraction (SPME) of some polycyclic aromatic hydrocarbons (PAHs) from water samples. The PANI film was directly electrodeposited on the platinum wire surface in sulfuric acid solution using cyclic voltammetry (CV) technique. The applicability of this coating was assessed employing a laboratory-made SPME device and gas chromatography with mass spectrometry (GC-MS) for the extraction of some PAHs from the headspace of aqueous samples. Application of wider potential range in CV led to a PANI with more stability against the temperature. The homogeneity and the porous surface structure of the...
A single layer deposition of Li-doped mesoporous TiO2beads for low-cost and efficient dye-sensitized solar cells, Article New Journal of Chemistry ; Volume 45, Issue 5 , 2021 , Pages 2470-2477 ; 11440546 (ISSN) ; Nouri, E ; Mohsenzadegan, N ; Mohammadi, M. R ; Martinez Chapa, S. O ; Sharif University of Technology
Royal Society of Chemistry 2021
Herein, we report a new strategy for improving the efficiency and reducing the fabrication cost of dye-sensitized solar cells (DSCs) by elimination of the three- or four-fold layer deposition of TiO2. This is performed by replacing a single layer deposition of mesoporous TiO2 beads, with sub-micrometer size, high surface area and tunable pore size, synthesized by a combination of sol-gel and solvothermal methods. Furthermore, superior electronic properties gained by a reduction in electronic trap states are achieved through doping of pristine TiO2 beads with lithium. The beads have a spherical shape with monodispersed texture consisting of anatase-TiO2 nanocrystals and ultra-fine pores. The...
Sol-gel-based solid-phase microextraction and gas chromatography-mass spectrometry determination of dextromethorphan and dextrorphan in human plasma, Article Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences ; Volume 818, Issue 2 , 2005 , Pages 147-157 ; 15700232 (ISSN) ; Eshaghi, A ; Rouini, M. R ; Sharif University of Technology
A novel solid-phase microextraction (SPME) method was developed for isolation of dextromethorphan (DM) and its main metabolite dextrorphan (DP) from human plasma followed by GC-MS determination. Three different polymers, poly(dimethylsiloxane) (PDMS), poly(ethylenepropyleneglycol) monobutyl ether (Ucon) and polyethylene glycol (PEG) were synthesized as coated fibers using sol-gel methodologies. DP was converted to its acetyl-derivative prior to extraction and subsequent determination. The porosity of coated fibers was examined by SEM technique. Effects of different parameters such as fiber coating type, extraction mode, agitation method, sample volume, extraction time, and desorption...
Synthesis and cytotoxicity assessment of superparamagnetic iron-gold core-shell nanoparticles coated with polyglycerol, Article Journal of Colloid and Interface Science ; Volume 345, Issue 1 , 2010 , Pages 64-71 ; 00219797 (ISSN) ; Simchi, A ; Khakpash, N ; Sharif University of Technology
Core-shell iron-gold (Fe@Au) nanoparticles were synthesized by a facile reverse micelle procedure and the effect of water to surfactant molar ratio (w) on the size, size distribution and magnetic properties of the nanoparticles was studied. MTT assay was utilized to evaluate the cell toxicity of the nanoparticles. To functionalize the particles for MRI imaging and targeted drug delivery, the particles were coated by polyglycerol through capping with thiol followed by polymerization of glycidol. The characteristics of the particles were examined by X-ray diffraction (XRD), transmission electron microscopy (TEM), vibrating sample magnetometere (VSM), UV-visible spectroscopy, and Fourier...
Molecularly imprinted polydopamine nano-layer on the pore surface of porous particles for protein capture in HPLC column, Article Journal of Colloid and Interface Science ; Volume 404 , 2013 , Pages 117-126 ; 00219797 (ISSN) ; Shojaei, A ; Abdekhodaie, M. J ; Sellergren, B ; Sharif University of Technology
Bio-inspired Human Serum Albumin (HSA) imprinted polydopamine nano-layer was produced through oxidative polymerization of dopamine on the pore surface of HSA modified porous silica particles. The coating thickness was controlled by the reaction time and thereby varied within 0-12. nm. The samples were characterized by elemental analysis, FT-IR, DSC, SEM, TEM, TGA, physisorption and thermoporometry. The characterization confirmed the success of evolution and deposition of polydopamine layer on the silica pore surface. Batch rebinding experiment showed that the molecularly imprinted polymer (MIP) with 8.7. nm coating thickness, in comparison with the thinner and thicker coatings, displays the...
Development of nanostructured porous TiO2 thick film with uniform spherical particles by a new polymeric gel process for dye-sensitized solar cell applications, Article Electrochimica Acta ; Volume 89 , February , 2013 , Pages 90-97 ; 00134686 (ISSN) ; Mohammadi, M. R ; Sharif University of Technology
A novel simple synthetic procedure for fabrication of high surface area nanostructured TiO2 electrode with uniform particles for photovoltaic application is reported. Modifying the TiO2 particulate sol by pH adjustment together with employment of a polymeric agent, so-called polymeric gel process, was developed. The polymeric gel process was used to deposit nanostructured thick electrode by dip coating incorporated in dye-sensitized solar cells (DSSCs). X-ray diffraction (XRD) analysis revealed that deposited film was composed of primary nanoparticles with average crystallite size in the range 21-39 nm. Field emission scanning electron microscope (FE-SEM) images showed that deposited film...
Effects of temperature on wear behavior of a plasma sprayed diesel engine cylinder, Article SAE Technical Papers ; 2012 ; Farrahi, G. H ; Eftekhari, M. R ; Sharif University of Technology
One of the main subjects in automotive industries is to enhance the efficiency of internal combustion engines. Wear between cylinder and ring is one of the major parameters reducing the engine performance. So many parameters are affecting the wear losses. Temperature plays a key role on the severity of wear condition in internal combustion engines. In conventional cast iron cylinders, it is not possible to increase the temperature from a defined level, as it causes excessive wear in contact area between cylinder liner and piston ring. One of the major benefits of using ceramic coating is their ability to withstand in higher temperatures, while having adequate hardness to improve wear rate...
Bed mixing and leachate recycling strategies to overcome pressure drop buildup in the biofiltration of hydrogen sulfide, Article Bioresource Technology ; Volume 109 , 2012 , Pages 26-30 ; 09608524 (ISSN) ; Torkian, A ; Aslani, H ; Dehghanzadeh, R ; Sharif University of Technology
The effects of leachate recycling and bed mixing on the removal rate of H 2S from waste gas stream were investigated. The experimental setup consisted of an epoxy-coated three-section biofilter with an ID of 8cm and effective bed height of 120cm. Bed material consisted of municipal solid waste compost and PVC bits with an overall porosity of 54% and dry bulk density of 0.456gcm -3. Leachate recycling had a positive effect of increasing elimination capacity (EC) up to 21gSm -3 bedh -1 at recycling rates of 75mld -1, but in the bed mixing period EC declined to 8g Sm -3bedh -1. Pressure drop had a range of zero to 18mm H 2Om -1 in the course of leachate recycling. Accumulation of sulfur reduced...
Fluorescent microscopy using localized excitation source with gold nanotriangles: A computational study, Article Photonics and Nanostructures - Fundamentals and Applications ; Volume 9, Issue 3 , 2011 , Pages 219-224 ; 15694410 (ISSN) ; Rashidian, B ; Vossoughi, M ; Sharif University of Technology
A new method for fluorescent microscopy has been proposed. Proposed method uses indirect excitation of fluorophores with nanometer localized illuminating source. Localized source is created at corners of gold nanotriangles which are deposited on glass substrate. Actually the combination of gold nanotriangle (deposited on glass) acts as active substrate (where species will be placed) for our proposed method. The structure will be scanned with a focused beam of laser (or combination of beams). Due to electric field enhancement in corners and edges of nanotringle (because of surface plasmons), third order nonlinear effect will be enhanced accordingly. Enhancement in third order nonlinearity...
A colorimetric sensor array for detection and discrimination of biothiols based on aggregation of gold nanoparticles, Article Analytica Chimica Acta ; Volume 882 , July , 2015 , Pages 58-67 ; 00032670 (ISSN) ; Hormozi-Nezhad, M.R ; Mahmoudi, M ; Sharif University of Technology
Developments of sensitive, rapid, and cheap systems for identification of a wide range of biomolecules have been recognized as a critical need in the biology field. Here, we introduce a simple colorimetric sensor array for detection of biological thiols, based on aggregation of three types of surface engineered gold nanoparticles (AuNPs). The low-molecular-weight biological thiols show high affinity to the surface of AuNPs; this causes replacement of AuNPs' shells with thiol containing target molecules leading to the aggregation of the AuNPs through intermolecular electrostatic interaction or hydrogen-bonding. As a result of the predetermined aggregation, color and UV-vis spectra of AuNPs...
Nanomechanical properties of TiO2 granular thin films, Article ACS Applied Materials and Interfaces ; Volume 2, Issue 9 , 2010 , Pages 2629-2636 ; 19448244 (ISSN) ; Taghavinia, N ; Keshavarz Alamdari, E ; Volinsky, A.A ; Sharif University of Technology
Post-deposition annealing effects on nanomechanical properties of granular TiO2 films on soda-lime glass substrates were studied. In particular, the effects of Na diffusion on the films' mechanical properties were examined. TiO2 photocatalyst films, 330 nm thick, were prepared by dip-coating using a TiO2 sol, and were annealed between 100 °C and 500 °C. Film's morphology, physical and nanomechanical properties were characterized by atomic force microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, differential thermo-gravimetric analysis, and nanoindentation. Contrary to expectations, the maximum film hardness was achieved for 300°C annealing, with a value of 0.69 ± 0.05 GPa....
Platinum nanoparticles with superacid-doped polyvinylpyrrolidone coated carbon nanotubes: Electrocatalyst for oxygen reduction reaction in high-temperature proton exchange membrane fuel cell, Article RSC Advances ; Volume 6, Issue 48 , 2016 , Pages 41937-41946 ; 20462069 (ISSN) ; Saievar Iranizad, E ; Bayat, A ; Sharif University of Technology
Royal Society of Chemistry 2016
In order to improve the catalytic activity and durability of proton-exchange-membrane-fuel-cells (PEMFCs), Nafion-free Pt-based catalyst using the superacid-doped polymer coated multiwall carbon nanotubes (MWCNTs) was investigated. The modification and nano polymerization of MWCNTs were developed by polyvinylpyrrolidone (PVP). The following observations were made in the presence of polymer: better dispersion of MWCNTs, higher thermal stability of MWCNT/PVP than that of pristine MWCNT up to 450 °C as tested by thermal gravimetric analysis (TGA), homogeneous distribution of Pt without agglomeration as observed by transmission electron microscope (TEM), and not too much difference in Pt loading...
Hydrothermal synthesis of ZnO nanorod arrays for photocatalytic inactivation of bacteria, Article Journal of Physics D: Applied Physics ; Volume 42, Issue 22 , 2009 ; 00223727 (ISSN) ; Mehrabian, M ; Mirabbaszadeh, K ; Azimirad, R ; Sharif University of Technology
Arrays of ZnO nanorods were synthesized on ZnO seed layer/glass substrates by a hydrothermal method at a low temperature of 70 °C. The effect of pH > 7 of the hydrated zinc nitrate-NaOH precursor on the morphology and topography (e.g. size, surface area and roughness), the optical characteristics (e.g. optical transmission and band-gap energy), hydrophilicity and antibacterial activity of the grown ZnO nanostructure and nanorod coatings were investigated. For pH = 11.33 of the precursor (NaOH concentration of 0.10M), a fast growth of ZnO nanorods on the seed layer (length of ∼1 νm in 1.5 h) was observed. The fast growth of the ZnO nanorods resulted in a significant reduction in the optical...
Multiphysics flow modeling and in vitro toxicity of iron oxide nanoparticles coated with poly(vinyl alcohol), Article Journal of Physical Chemistry C ; Volume 113, Issue 6 , 2009 , Pages 2322-2331 ; 19327447 (ISSN) ; Shokrgozar, M. A ; Simchi, A ; Imani, M ; Milani, A. S ; Stroeve, P ; Vali, H ; Häfeli, U. O ; Bonakdar, S ; Sharif University of Technology
This study investigated the behavior of ferrofluids containing superparamagnetic iron oxide nanoparticles (SPION) of various compositions for potential applications in drug delivery and imaging. To ensure biocompatibility, the interaction of these SPION with two cell lines (adhesive and suspended) was also investigated using an MTT (3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide) assay. The cell lines studied were primary mouse connective tissue cells (adhesive) and human leukemia cells (suspended). SPION were synthesized with a co-precipitation method under different stirring rates and NaOH molarities. The SPION demonstrated a range of magnetic saturations due to their...
Design of an effective piezoelectric microcantilever biosensor for rapid detection of COVID-19, Article Journal of Medical Engineering and Technology ; Volume 45, Issue 6 , 2021 , Pages 423-433 ; 03091902 (ISSN) ; Merati, M ; Abdekhodaie, M. J ; Sharif University of Technology
Taylor and Francis Ltd 2021
Acute respiratory syndrome coronavirus 2 (SARS-CoV-2), also called COVID-19, is one of the most contagious viruses resulting in a progressive pandemic. Since specific antiviral treatments have not been developed yet and its fatal rate is almost high, early and fast detection is critical for controlling the outbreak. In this study, a piezoelectric microcantilever biosensor has been designed for detecting COVID-19 samples directly without requiring preparation steps. The biosensor acts as a transducer and is coated with the related antibody. When the SARS-CoV-2 antigens adsorbed on the microcantilever top surface through their spike proteins, a surface stress due to the mass change would be...
An unbreakable on-line approach towards sol-gel capillary microextraction, Article Journal of Chromatography A ; Volume 1218, Issue 26 , 2011 , Pages 3952-3957 ; 00219673 (ISSN) ; Piri-Moghadam, H ; Es'haghi, A ; Sharif University of Technology
In this work a novel unbreakable sol-gel-based in-tube device for on-line solid phase microextraction (SPME) was developed. The inner surface of a copper tube, intended to be used as a high performance liquid chromatography (HPLC) loop, was electrodeposited by metallic Cu followed by the self assembled monolayers (SAM) of 3-(mercaptopropyl) trimethoxysilane (3MPTMOS). Then, poly (ethyleneglycol) (PEG) was chemically bonded to the -OH sites of the SAM already covering the inner surface of the copper loop using sol-gel technology. The homogeneity and the porous surface structure of the SAM and sol-gel coatings were examined using the scanning electron microscopy (SEM) and adsorption/desorption...
Examination of chondroitinase ABC I immobilization onto dextran-coated Fe3O4 nanoparticles and its in-vitro release, Article Journal of Biotechnology ; Volume 309 , 2020 , Pages 131-141 ; Vossoughi, M ; Khajeh, K ; Alemzadeh, I ; Sharif University of Technology
Elsevier B.V 2020
Chondroitinase ABC I (cABC I) has received notable attention in treatment of spinal cord injuries and its application as therapeutics has been limited due to low thermal stability at physiological temperature. In this study, cABC I enzyme was immobilized on the dextran-coated Fe3O4 nanoparticles through physical adsorption to improve the thermal stability. The nanoparticles were characterized using XRD, SEM, VSM, and FTIR analyses. Response surface methodology and central composite design were employed to assess factors affecting the activity of immobilized cABC I. Experimental results showed that pH 6.3, temperature 24 °C, enzyme/support mass ratio 1.27, and incubation time 5.7 h were the...
Three-dimensional hybrid of iron–titanium mixed oxide/nitrogen-doped graphene on Ni foam as a superior electrocatalyst for oxygen evolution reaction, Article Journal of Colloid and Interface Science ; Volume 563 , 15 March , 2020 , Pages 241-251 ; Asen, P ; Shahrokhian, S ; Irajizad, A ; Sharif University of Technology
Academic Press Inc 2020
Growing demands for clean and renewable energy technologies have sparked broad research on the development of highly efficient and stable non-noble metal electrocatalysts for oxygen evolution reaction (OER). In this regard, in the present work a three-dimensional Fe2TiO5/nitrogen-doped graphene (denoted as 3D FTO/NG) hybrid electrocatalyst was synthesized via a facile in-situ process using a hydrothermal method. Structural characterization of the prepared nanocomposite is performed by various techniques e.g. field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM) analysis, Fourier transform infrared spectra (FT-IR), X-ray photoelectron spectroscopy spectra (XPS),...
Polymer-Coated NH2-UiO-66 for the codelivery of DOX/pCRISPR, Article ACS Applied Materials and Interfaces ; Volume 13, Issue 9 , 2021 , Pages 10796-10811 ; 19448244 (ISSN) ; Bagherzadeh, M ; Heidarian Haris, M ; Ghadiri, A. M ; Matloubi Moghaddam, F ; Fatahi, Y ; Dinarvand, R ; Jarahiyan, A ; Ahmadi, S ; Shokouhimehr, M ; Sharif University of Technology
American Chemical Society 2021
Herein, the NH2-UiO-66 metal organic framework (MOF) has been green synthesized with the assistance of high gravity to provide a suitable and safe platform for drug loading. The NH2-UiO-66 MOF was characterized using a field-emission scanning electron microscope, transmission electron microscope (TEM), X-ray diffraction, and zeta potential analysis. Doxorubicin was then encapsulated physically on the porosity of the green MOF. Two different stimulus polymers, p(HEMA) and p(NIPAM), were used as the coating agents of the MOFs. Doxorubicin was loaded onto the polymer-coated MOFs as well, and a drug payload of more than 51% was obtained, which is a record by itself. In the next step, pCRISPR was...