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electrophoretic-depositions
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Characterization and antibacterial performance of electrodeposited chitosan–vancomycin composite coatings for prevention of implant-associated infections [electronic resource]
, Article Journal of Materials Science and Engineering: C ; 1 August 2014, Volume 41, Pages 240–248 ; Tamjid, E ; Simchi, A. (Abdolreza) ; Sharif University of Technology
Abstract
Orthopaedic implant-associated infections are one of the most serious complications in orthopaedic surgery and a major cause of implant failure. In the present work, drug-eluting coatings based on chitosan containing various amounts of vancomycin were prepared by a cathodic electrophoretic deposition process on titanium foils. A three-step release mechanism of the antibiotic from the films in a phosphate-buffered saline solution was noticed. At the early stage, physical encapsulation of the drug in the hydrogel network controlled the release rate. At the late stage, however, in vitro degradation/deattachment of chitosan was responsible for the controlled release. Cytotoxicity evaluation of...
Electrophoretic deposition of titanium dioxide nano-powders films in isopropanol as a solvent
, Article International Journal of Modern Physics B ; Volume 22, Issue 18-19 , 2008 , Pages 2989-2994 ; 02179792 (ISSN) ; Roushan Afshar, M ; Sharif University of Technology
World Scientific Publishing Co. Pte Ltd
2008
Abstract
In this study, titanium dioxide nano powders were electrophoretically deposited on the stainless steel in Isopropanol and Triethanolamine as a solvent and dispersant, respectively. The effects of deposition parameters including deposition voltage (5 to 20 V) and deposition time (5 to 60 s) on the microstructure and surface topography were examined by scanning electron microscope (SEM) and scanning probe microscope (SPM), respectively. In addition, the effects of these deposition parameters on packing density were investigated. This research revealed that substrate surface is fully covered with increasing deposition voltage and deposition time. Therefore packing density of deposited films is...
Electrophoretic deposition of porous hydroxyapatite coatings using polytetrafluoroethylene particles as templates
, Article Materials Science and Engineering C ; Volume 27, Issue 5-8 SPEC. ISS , 2007 , Pages 1482-1486 ; 09284931 (ISSN) ; Afshar, A ; Chen, J ; Zhang, X ; Sharif University of Technology
2007
Abstract
The formation of macroporous bioactive hydroxyapatite(HA) coatings using polytetrafluoroethylene(PTFE) particles were studied. The porous HA coatings were prepared onto a pure titanium substrate by electrophoretic deposition(EPD) at 120 V for 1.5 min using ethanol suspensions mixture of HA (500 nm in size) and PTFE (1-3 μm in size) particles. Subsequently, the composite coatings obtained by EPD were heated at 900 °C for 60 min to disintegrate the organic PTFE particles and sinter the inorganic HA particles. The calcinations of the PTFE led to the formation of porosity in the HA coating. These results demonstrate a new method for creating porous HA coatings on titanium. © 2006 Elsevier B.V....
Graphene oxide sheets involved in vertically aligned zinc oxide nanowires for visible light photoinactivation of bacteria
, Article Journal of Alloys and Compounds ; Vol. 612 , 2014 , pp. 380-385 ; ISSN: 09258388 ; Rahighi, R ; Akhavan, O ; Moshfegh, A ; Sharif University of Technology
Abstract
Vertically aligned ZnO nanowires (NWs) hybridized with reduced graphene oxide sheets (rGO) were applied in efficient visible light photoinactivation of bacteria. To incorporate graphene oxide (GO) sheets within the NWs two different methods of drop-casting and electrophoretic deposition (EPD) were utilized. The EPD method yielded effective penetration of the positively charged GO sheets into the NWs to form a spider net-like structure, whereas the drop-casting method resulted in only a surface coverage of the GO sheets on top of the NWs. The electrical connection between the EPD-incorporated sheets and the NWs was checked by monitoring the electron transfer from UV-assisted photoexcited ZnO...
Development of electrophoretically deposited hydroxyapatite coatings on anodized nanotubular TiO2 structures: Corrosion and sintering temperature
, Article Applied Surface Science ; Vol. 301 , May , 2014 , pp. 250-257 ; ISSN: 01694332 ; Batmanghelich, F ; Afshar, A ; Dolati, A ; Mortazavi, G ; Sharif University of Technology
Abstract
Hydroxyapatite (HA) coatings in and onto anodized TiO2 nanotube arrays were presented and prepared by electrophoretic deposition technique (EPD). Coatings were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). EPD proved to be an innovative and versatile technique to coat HA on and into nanotubular structures of TiO2 with enhanced adhesion between nanotubes and HA particles provided by mechanical interlocking. After EPD of HA on TiO2 layer, samples were sintered at 400 °C, 600 °C and 800 °C for 2 h in an Ar atmosphere. Effect of EPD processing parameters on thickness of the deposits and rate of deposition was elucidated for HA coatings on the nanotubular TiO2...
Electrophoretic deposition of functionally-graded NiO-YSZ composite films
, Article Journal of the European Ceramic Society ; Volume 33, Issue 10 , 2013 , Pages 1815-1823 ; 09552219 (ISSN) ; Yar, A. Y ; Vafaeenezhad, S ; Sani, M. A. F ; Simchi, A ; Sharif University of Technology
2013
Abstract
Functionally-graded NiO-8. mol % YSZ composite films were prepared by a controlled voltage-decay electophoretic deposition (EPD) process. The films consisted of three layers with varying NiO concentrations and porosities. Effects of different parameters including the type of the organic media, solid concentration, NiO:YSZ ratio, and iodine on the stability of EPD suspensions and deposition kinetics were studied. A stable NiO-YSZ suspension was attained in isopropanol with NiO-YSZ ratio of 60:40 and iodine concentration of 0.5. mM. The composite film contained varying NiO concentration from 46. wt.% near the substrate to 32. wt.% close to the electrolyte with 42. wt% NiO in the intermediate...
Electrophoretic deposition of ZnO–CeO2 mixed oxide nanoparticles
, Article Journal of the American Ceramic Society ; Volume 100, Issue 3 , 2017 , Pages 901-910 ; 00027820 (ISSN) ; Aliofkhazraei, M ; Hosseinali, M ; Sharif University of Technology
Blackwell Publishing Inc
2017
Abstract
ZnO–CeO2 nanoparticles were synthesized by microwave combustion and deposited by electrophoretic deposition (EPD). The effect of using two different alcohols, ethanol and methanol, was investigated on EPD behavior and morphology of deposited film. Moreover, the effect of concentration of nanoparticles and applied voltage on the mass of deposit and the variation in the current density were investigated. With a change in the alcohol type, the surface morphology of deposition changed and some voids were observed on the deposition surface in ethanol. In all cases, with increasing concentration of nanoparticles in suspension, the number of developed cracks increased. Besides, a rise in voltage...
An Investigation on Zirconia Nano-particles Coating Deposited on Magnesium AZ91 alloy Using Electrodeposition Method
, M.Sc. Thesis Sharif University of Technology ; Afshar, Abdollah (Supervisor)
Abstract
Recently magnesium alloys have shown great potential as biodegradable metallic implants. However, due to high corrosion rate in the body environment, these alloys would be degraded before the tissue healing time period. Therefore corrosion resistance of these alloys has to be improved in order to be used in biological environments. In the present work, supposing improvement of corrosion properties of magnesium AZ91D alloy, the alloy has been coated with biocompatible nano-Zirconia particles using Electrophoretic deposition method and the effects of deposition parameters such as bath agitation, Zirconia concentration, current density and duration of deposition process on the properties of the...
Synthesis of Antibiotic-eluting Chitosan-based Composite Coating by Electrophoretic Deposition for Bone Implants
, M.Sc. Thesis Sharif University of Technology ; Simchi, Abdol Reza (Supervisor) ; Bagheri, Reza (Supervisor)
Abstract
Drug-eluting bone implant coatings is a new era that has gained a lot of attention in recent years. In this matter, drug is loaded in the coating and local and targeted release of the drug results in preventing the side effects of implantation and increasing the healing process of the patient. The aim of this project was to synthesis the antibiotic eluting chitosan-based composite using electrophoretic deposition for bone implant coating. By using electrophoretic deposition chitosan and chitosan-bioglass composite coatings were synthesized. Then the probability of loading of drug into coating by using electrophoretic deposition was evaluated and by using this process chitosan and...
Synthesis of Graphene Nanosheets for Application in Biosensors
, M.Sc. Thesis Sharif University of Technology ; Akhavan, Omid (Supervisor)
Abstract
Graphene, the newborn nanomaterial whose unique properties has extensively drawnattention of many scientists in the recent years, is an ideal candidate for sensing applications due to its exclusive properties like extremely high specific surface area, excellent electrical conductivity, andcapability of being easily functionalized. In this research, after reviewing the attempts already performed on detection of DNA, in order to detect the four bases of DNA (G, A, T, and C) via electrochemical approach, graphene nanosheets were synthesized by the popular Hummer’s method and were deposited on a graphite rod by electrophoretic deposition with a vertical preferred orientation. To eliminate the...
Electrophoretic deposition of Ni/SiO2 nanocomposite coating: Fabrication process and tribological and corrosion properties
, Article Journal of Nano Research ; Volume 26 , 6 January , 2014 , Pages 45-51 ; ISSN: 16625250 ; Ghorbani, M ; Sharif University of Technology
Abstract
To the best of our knowledge, this work presents the first successful effort to fabricate and study nanostructured Ni-based composite coatings using the electrophoretic deposition method with nanostructured SiO2 particles. In this work, Ni/SiO2 nanoparticle composite coatings were prepared by electrophoretic deposition (EPD) [1] and their hardness, wear and corrosion resistances [2] were examined. After studying the morphology of the coatings and finding the optimum conditions for uniform coating, in order to improve the mechanical properties as well as resistance to corrosion, sintering was performed. The Ni/SiO2 nanocomposite coatings show excellent hardness (∼376 HV), reduced Young's...
Effect of pH and carbon nanotube content on the corrosion behavior of electrophoretically deposited chitosan-hydroxyapatite-carbon nanotube composite coatings
, Article Ceramics International ; Volume 39, Issue 5 , July , 2013 , Pages 5393-5402 ; 02728842 (ISSN) ; Ghorbani, M ; Sharif University of Technology
2013
Abstract
In the first stage, chitosan (CH)-hydroxyapatite (HA)-multiwalled carbon nanotube (MWCNT) composite coatings were synthesized by electrophoretic deposition technique (EPD) on 316L stainless steel substrates at different levels of pH and characterized by X-ray diffraction (XRD), Raman spectroscopy, FTIR and field emission scanning electron microscopy (FESEM). A smooth distribution of HA and MWCNT particles in a chitosan matrix with strong interfacial bonding was obtained. In the next stage, effects of pH and MWCNT content of the suspension on the corrosion behavior and deposition mechanism were studied. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) curves...
Electrophoretic deposition of nano-zirconia coating on AZ91D magnesium alloy for bio-corrosion control purposes
, Article Surface and Coatings Technology ; Volume 311 , 2017 , Pages 182-190 ; 02578972 (ISSN) ; Mohammadi, I ; Afshar, A ; Sharif University of Technology
Elsevier B.V
2017
Abstract
Magnesium alloys are considered as potential biodegradable biomaterials in hard tissue implants. However, the fast degradation rate of these alloys in the biological environment causes failure of the implant just prior to the desirable time. In the present work, in order to decrease and curb the bio-corrosion rate of AZ91D Magnesium alloy, zirconia, which is classified as a biocompatible ceramic, was coated on the alloy surface through electrophoretic deposition (EPD) technique. The effects of alterations in the EPD parameters such as current density, duration time and ZrO2 particles concentration on coating properties including thickness, morphology and adhesion were then characterized....
Effects of electrophoretic deposition parameters on the photocatalytic activity of TiO2 films: Optimization by response surface methodology
, Article Colloids and Surfaces A: Physicochemical and Engineering Aspects ; Vol. 452, Issue. 1 , 2014 , pp. 1-8 ; ISSN: 09277757 ; Vossoughi, M ; Feilizadeh, M ; Rashtchian, D ; Moradi, S ; Alemzadeh, I ; Sharif University of Technology
Abstract
In this work, the electrophoretic deposition method was utilized to immobilize TiO2 particles on stainless steel substrates. In addition, for the first time, statistics-based experimental design using response surface methodology was employed to investigate the effect of four key coating parameters (i.e. applied voltage, calcination temperature, photocatalyst weight percentage, and deposition time) on the photocatalytic degradation. Analysis of variance revealed that the proposed model was adequate. X-ray diffraction and scanning electron microscope were used to evaluate the effects of the parameters on degradation efficiency. The optimum applied voltage, calcination temperature, catalyst...
Electrophoretic Deposition of Titanium Dioxide for Fabrication of Photoanode of Dye Sensitized Solar Cell
, M.Sc. Thesis Sharif University of Technology ; Taghavinia, Nima (Supervisor)
Abstract
This research is focused on fabrication of TiO2 layers by electrophoretic deposition (EPD) for application as photoanode in Dye Sensitized Solar Cell (DSC). DSCs are third generation of solar cells, also known as the Grätzel cell, after its inventor Michael Grätzel. A DSC is composed of a porous layer of wide band gap semiconductor such as TiO2 and ZnO, covered with a molecular dye that absorbs sunlight, and a counter electrode contacted by a liquid redox electrolyte. Dye Sensitized semiconductor (photoanode) has important role in conversion of photon to electricity. To achieve higher efficiency, preparation of photoanode with high surface area resulted to enough dye adsorption is necessary....
Electrophoretic Deposition of (Mn,Co)3O4 Spinel Coating for Solid Oxide Fuel Cell Interconnects
, M.Sc. Thesis Sharif University of Technology ; Faghihi Sani, Mohammad Ali (Supervisor) ; Simchi, Abdol Reza (Supervisor)
Abstract
Solid oxide fuel cell (SOFC) is one of the promising candidates for clean energy production. Due to the high operating temperature of SOFC, a protective coating is commonly applied on the surface of interconnects to prevent oxidation. In this study, electrophoretic deposition was employed to prepare a manganese-cobalt spinel coating on the surface of ferritic stainless steel (AISISAE430) substrates. MnCo2O4 powder with an average particle size of 60 nm was utilized and the sintering behavior of the coatings at different temperatures was studied. Non-isothermal and isothermal sintering behavior of the powder compacts were examined by employing a sensitive dilatometer. Master sintering curve...
Evaluation of Controlled Drug Release Chitosan-based Coatings on Titanium Implants: Microstructure, Bioactivity and Biocompatibility
, Ph.D. Dissertation Sharif University of Technology ; Simchi, Abdolreza (Supervisor)
Abstract
Implant-associated infections are one of the most serious complications in orthopaedic and trauma surgery as it may result in poor functional outcome, implant failure, chronic osteomyelitis or even death. Great concerns have been taken to reduce implant-associated infections through progressing in operating standards, minimizing the possibility of contamination during surgery, reducing the establishment of infection by perioperative antibiotic prophylaxis, and confining of pathogenic strains by patient isolation. In spite of these preventions, the percentage of postoperative infections is still rising. Composite coatings with bone-bioactivity and drug-eluting capacity are considered as...
The Effect of Solvent Type on the Characteristic of TiO2 Nanometric Coatings Produced by Electrophoretic Method
, M.Sc. Thesis Sharif University of Technology ; Ghorbani, Mohammad (Supervisor)
Abstract
Titania is semiconductor material and have many applications including photocatalysis, photochromic, air and water purification, sensors, and solar cell. In electrophoretic deposition, charged particles dispersed in a stable suspension move towards an oppositely charged electrode, and form dense layer of deposit on it. In this investigation electrophoretic deposition of titania nano-particles in suspensions prepared by different solvents (methanol, ethanol and butanol) with and without dispersant (triethanolamine and polyethylenimine), was studied. Well stabilized suspensions, prepared for electrophoretic deposition. The effects of solvent type, additive concentration, mechanism of particles...
A study of the electrophoretic deposition of bioactive glass-chitosan composite coating
, Article Ceramics International ; Volume 38, Issue 1 , January , 2012 , Pages 471-476 ; 02728842 (ISSN) ; Afshar, A ; Sharif University of Technology
2012
Abstract
Bioactive glass is coated on implant's surface to improve corrosion resistance and osseointegration, when placed in the body. Bioactive glass particles were synthesized through a sol-gel process and deposited along with chitosan to form a composite coating on a stainless steel substrate using electrophoretic deposition technique. Stable suspensions of chitosan-bioactive glass were prepared using bioactive glass particles (<1 μm) and 0.5 g/l chitosan solution. The influence of ethanol-water ratio on deposition yield was investigated. For all process conditions, best results were achieved with suspension of 30 vol% water in ethanol-water containing 2 g/l bioactive glass. FTIR studies showed...
Silver fiber fabric as the current collector for preparation of graphene- based supercapacitors
, Article Electrochimica Acta ; Volume 227 , 2017 , Pages 246-254 ; 00134686 (ISSN) ; Shahrokhian, S ; Iraji zad, A ; Sharif University of Technology
Elsevier Ltd
2017
Abstract
During the past few years, a considerable attention has been devoted to the development of textile- based energy storage devices and wearable electronics applications. In this paper, for the first time, we report a flexible high performance graphene-based supercapacitor using silver fiber fabric as the current collector. The silver fiber fabric offers remarkable advantages such as light weight, mechanical flexibility and ease of integration with electronic textiles, which well-suited for wearable energy storage devices. A new hybrid material of graphene-silver fiber fabric (rGO/SFF) was prepared through a facile electrophoretic deposition of graphene and being used as a binder-free flexible...