Akbar Eshaghi - Academia.edu (original) (raw)

Volume 7_Issue 2 by Akbar Eshaghi

In this research work, silica nano-porous thin films were deposited on glass substrates by layer ... more In this research work, silica nano-porous thin films were deposited on glass substrates by layer by layer method. The thin films were calcinated at various calcination temperatures (200, 300, 400, and 500 °C). The morphology, surface characteristics, surface roughness and hydrophilic properties of the thin films were investigated by field emission scanning electron microscopy, attenuated total reflectance fourier transform infrared spectroscopy, atomic force microscopy and water contact angle analyzer. The surface characteristic showed that silica nano-porous thin film had an amorphous structure. The hydrophilic results indicated that the water contact angle of the glass coated silica nano-porous surface is decreased by increasing the calcinations temperatures to 300 °C and at higher temperature, it is increased. The deposition of silica nano-porous thin film on the glass surface at the optimum calcination temperature (300 °C) decreased water contact angle of the glass surface from 67° to 3°. Therefore, silica nanoporous thin film calcinated at 300 °C showed superhydrophilicity which greatly encourages the antifogging functions of the thin film.

Papers by Akbar Eshaghi

استقلال, Sep 1, 2019

In this research, MgF2-2%SiO2/MgF2 thin films were applied on a glass substrate. At first, MgF2 t... more In this research, MgF2-2%SiO2/MgF2 thin films were applied on a glass substrate. At first, MgF2 thin films with the optical thickness were deposited on the glass slide substrates. Then, MgF2-2%SiO2 thin films were deposited on the glass coated with MgF2 thin films. Finally, the nanocomposite thin films were surface treated by the PFTS solution. Characterization of the thin film was done by X-Ray defractometry (XRD), attenuated total reflectance fourier transform infrared spectroscopy (ATR-FTIR), UV-Vis spectroscopy, and atomic force microscopy (AFM) techniques. Also, the hydrophobic properties of the samples were investigated by measuring the contact angle of the water. The results showed that the deposition of the six layer MgF2 thin

Iranian Journal of Materials Science and Engineering, Mar 10, 2018

Bulletin of The Korean Chemical Society, Nov 20, 2011

TiO2-SiO2-In2O3 nanocomposite thin film was deposited on the glass substrates using a dip coating... more TiO2-SiO2-In2O3 nanocomposite thin film was deposited on the glass substrates using a dip coating technique. The morphology, surface composition, surface hydroxyl groups, photocatalytic activity and hydrophilic properties of the thin film were investigated by AFM, XPS, methyl orange decoloring rate and water contact angle measurements. The hydroxyl content for TiO2, TiO2-SiO2 and TiO2-SiO2-In2O3 nanocomposite films was calculated to be 11.6, 17.1 and 20.7%, respectively. TiO2-SiO2-In2O3 film turned superhydrophilic after 180min irradiation with respect to pure TiO2 and TiO2-SiO2 thin films. The photocatalytic decomposition of methyl orange for TiO2, TiO2-SiO2 and TiO2-SiO2-In2O3 thin films was measured as 38.19, 58.71 and 68.02%, respectively. The results indicated that SiO2 and In2O3 had a significant effect on the hydrophilic, photocatalytic and self-cleaning properties of TiO2 thin film.

Arabian Journal of Chemistry, May 1, 2023

Diamond and Related Materials, Mar 1, 2020

In the current study, the Ge 1−x-C x :H films were deposited on silicon and glass substrates by a... more In the current study, the Ge 1−x-C x :H films were deposited on silicon and glass substrates by a plasma-enhanced chemical vapor deposition (PECVD) process with a gas mixture of GeH 4 and CH 4 as the precursors. For characterizing the films, field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), Rutherford backscattering spectrometry, elastic recoil detection analysis, and adhesion test were used. Based on the results, the growth mechanism of Ge 1−x-C x :H films by PECVD process was suggested as three separate steps including 1) the removal of surface H and the formation of dangling bonds, 2) insertion of germanium and methane radicals into the dangling bonds and 3) removal of inter-atomic H and the formation of GeeGe, CeC and GeeC transverse bonds, respectively. If in the growth environment the radicals XH 3 (X = Ge, C) be the dominant radicals, a two-dimensional growth occurs. On the other hand, the presence of a variety of radical species (XH 3 , XH 2 , XH) results in a preferred three-dimensional growth. With increasing the CH 4 : GeH 4 flow rate ratio, the surface homogenization mechanism by H ions becomes more prevalent and consequently, the threedimensional growth tends to the two-dimensional growth.

Progress in Organic Coatings, Mar 1, 2019

In this research, GPTMS-silica nano-hybrid coatings were immobilized on polycarbonate (PC) substr... more In this research, GPTMS-silica nano-hybrid coatings were immobilized on polycarbonate (PC) substrates by a solgel method. Perfluorooctyl-trichlorosilane (PFTS) was utilized to modify the prepared nano-hybrid coating surface. The modified nano-hybrid coatings were characterized by Field Emission Scanning Electron Microscope (FE-SEM), Energy Dispersive X-ray Spectrometry (EDS), atomic force microscopy (AFM), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), UV-vis-NIR spectrophotometer, and water contact angle analyzer methods. In addition, the self-cleaning properties of the nano-hybrid coatings were investigated. The results indicated that the formation of the nano-hybrid film improved the hardness and transmittance of the PC substrate. FE-SEM image indicated the formation of the crack free coating on the PC substrate. In addition, the modified nano-hybrid coating displays hydrophobicity (CA, 110°) and is very efficient at removing dust through water droplets.

Optik, Jun 1, 2016

Nano-structured Al and Ti co-doped ZnO (ATZO) thin films were synthesized with different concentr... more Nano-structured Al and Ti co-doped ZnO (ATZO) thin films were synthesized with different concentrations of Ti (0.1-0.5 at.%) by sol-gel method. The X-ray diffraction (XRD) analysis, field emission scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM) methods were used to investigate the structure, morphology, and surface roughness of the thin films. The optical properties were investigated by spectroscopic ellipsometry (SE) and UV-vis spectrophotometry methods. The XRD results revealed the wurtzite structure for all the samples. Increase in the Ti content resulted in reduction of the crystal size from 23 to 15 nm, along with decrease in the surface roughness of the samples from 8.2 to 3.4 nm. The optical measurement demonstrates that the band gap energy (E g) increases from 3.26 to 3.31 eV. It was observed that the resistivity increase with the increase in the Ti content, meanwhile, the transmittance decrease with the increase in the Ti content.

Materials research express, Aug 7, 2019

In this study, the phase transformations and mechanical properties of a Cu-bearing high-strength ... more In this study, the phase transformations and mechanical properties of a Cu-bearing high-strength low-carbon (HSLC) steel microalloyed with Nb were investigated. The phase transformations were studied by dilatometry and then the microstructures were evaluated. Mechanical properties were measured after various cycles of heat treatment. The results showed that the microstructure of this steel, at the cooling rates studied here, includes a mixture of bainite and martensite. The relatively high amounts of the substitutional elements such as Ni, as well as the low carbon content, resulted in the proximity of the bainite and martensite start temperatures. The Bs and Ms temperatures were determined to be 325 and 315 ?C, respectively. This led to the formation of coalesced bainite in the microstructure. The maximum hardness of the alloy was obtained at the aging temperature of 450 ?C. Additionally, the optimal combination of yield strength and impact energy was obtained by a single-stage aging treatment at 575 ?C for 1 h. The reason for the toughness improvement can be attributed to the formation of the precipitated austenite between the martensitic lathes during the aging process.

Optical and Quantum Electronics, Jan 21, 2017

In this work, silica nano-porous thin films were deposited on glass substrates by a layer-by-laye... more In this work, silica nano-porous thin films were deposited on glass substrates by a layer-by-layer assembly method. The environmental stability of the thin films was investigated under the salt spray conditions and UV irradiation. XPS, ATR-FTIR, FE-SEM, AFM, UV-Vis spectrophotometer and water contact angle measurements (WCAs) were used to characterize the thin films. The results showed that under the salt spray conditions and UV irradiation, both hydrophilicity and transparency of the thin film were reduced. Under the salt spray conditions at different exposure times of 5, 10, 15 and 20 h, the WCA increased from 3°for silica nano-porous thin film to 13°, 21°, 23°and 26°, respectively, and the transmittance also decreased from the average value of 97% of the thin film to 95.8, 95.3, 95 and 94.7%, respectively. Under the UV irradiation at different times of 5, 20 and 60 days, the WCA increased to 14°, 27°and 30°, and the transmittance also decreased to 95.1, 94.9, and 94%.

Surface & Coatings Technology, Sep 1, 2016

The structure of TiN x films formed by low energy ion-assisted deposition has been investigated b... more The structure of TiN x films formed by low energy ion-assisted deposition has been investigated by electron microscopy techniques. A dual ion beam system was used for the deposition with two Kaufman sources; one producing a 1 keY beam for sputtering Ti, the other a 100-400 eV argon or nitrogen ion beam. The variables of the experiment are the ion energy (100-400 eV), ion species (Ar+ or Ni), ion/atom arrival ratio, the angle of incidence of the ions with respect to the film and the partial pressure of nitrogen during deposition. The structure of the films has been examined using a 200 ke V electron microscope for production of electron diffraction patterns and bright and dark field images of the films. It is found that films formed by reactive sputtering (i.e., no ion bombardment) are single phase TiN x which has fcc structure. The grain sizes of the microcrystals, which are randomly orientated, are 10-15 nm. Ion bombardment during deposition generally leads to strong preferential (100) orientation of the microcrystals parallel to the surface of the film and this is coupled with a reduction in the grain size of the microcrystals in the film. Grain growth also appears to take place approximately along the direction of bombarding ions. Results suggest that the degree of orientation depends on the added energy per atom during deposition, indeed there seems to be an energy 'window' within which strong, preferred orientations are observed.

Materials Chemistry and Physics, Nov 1, 2018

In this work, hollow SiO 2-SiO 2 nanocomposite thin film was deposited on a glass substrate by a ... more In this work, hollow SiO 2-SiO 2 nanocomposite thin film was deposited on a glass substrate by a sol-gel dip-coating method. Transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM) were used to investigate the structure and morphology of the nanoparticles and films. Surface wettability and optical properties of the thin films were studied by means of water contact angle analyzer and UV-vis spectrophotometer, respectively. Beside, durability tests were performed to evaluate the environmental stability of the thin films. The results revealed that the diameter and shell thickness of the hollow silica nanoparticles were 80 nm and 20 nm, respectively. In addition, the thin film coated on the glass substrate increased the maximum transmission of glass substrate from 91.3 to 97.1% and reduced the water contact angle from 59 to 2 degrees. Also, durability tests indicated that this film has good stability in the environmental conditions. Therefore, hollow SiO 2-SiO 2 nanocomposite thin film has a high potential for development of the antireflective and antifogging coating for optical instruments.

Materials Chemistry and Physics, Feb 1, 2021

Superhydrophobicity is evolutionarily adaptive to surrounding environment. Lotus flower is natura... more Superhydrophobicity is evolutionarily adaptive to surrounding environment. Lotus flower is naturally occurring superhydrophobicity. Artificial self-cleaning materials function effectively on superhydrophobic surfaces so that water droplets bead up and roll off the surface taking the contamination particles away. Inspired by lotus flower, we have fabricated superhydrophobic Mg alloy surfaces using manganese dioxide (MnO 2) microspheres encased in stearic acid shells. The prepared superhydrophobic Mg alloy surface provides exceptional self-cleaning ability in air and oil, and remains non-wetting even after dynamic water shear, or exposure to strong acid, strong base, and saline solutions as well as organic solvents showing excellent mechanochemical durability, with broad application prospect.

Optik, Dec 1, 2015

Abstract In this research, titanium zinc oxide nanostructured thin film (0.5 wt% Ti) was deposite... more Abstract In this research, titanium zinc oxide nanostructured thin film (0.5 wt% Ti) was deposited on glass substrate by a sol–gel method. The structure, morphology, surface roughness, and surface composition of the thin films were investigated by X-ray diffraction, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy and atomic force microscopy. The optical and electrical properties of the thin films were investigated by UV NIR spectrophotometer and I–V characteristics. The X-ray diffraction pattern showed that the titanium zinc oxide thin film had a polycrystalline structure. The optical and electrical results indicated that titanium addition increased the band gap of the zinc oxide from 3.340 to 3.346 eV whereas resistivity of zinc oxide decreased from 8.2 × 104 to 3.8 × 104 O cm.

Journal of Nanostructures, Apr 1, 2017

Journal of Non-crystalline Solids, Dec 1, 2014

In this research, silica nano-porous thin films were deposited on glass substrates by layer-by-la... more In this research, silica nano-porous thin films were deposited on glass substrates by layer-by-layer assembly process. The structure, morphology, surface characteristics, surface roughness, and optical and hydrophilic properties of the thin film were investigated. The X-ray diffraction analysis shows that the silica nano-porous thin film has an amorphous structure. The transmittance spectra revealed that the silica nanoporous thin film increased transparency of the glass substrate from 91.8% to 97% at 550 nm. In addition, the silica nanoporous thin film decreased water contact angle of glass surface from 67°to 3°. Therefore, silica nanoporous thin film showed high transparency and superhydrophilicity which greatly encourage the antireflection and antifogging functions of the thin film.

DOAJ (DOAJ: Directory of Open Access Journals), Sep 1, 2013

SiO 2 /TiO 2 /SiO 2 thin films were deposited on glass substrates using an electron beam physical... more SiO 2 /TiO 2 /SiO 2 thin films were deposited on glass substrates using an electron beam physical vapor deposition technique. The structure, morphology, surface composition, surface roughness, optical properties, and hydrophilic properties of the thin film were investigated. The structure measurement shows that only anatase phase was exhibited in the thin film. In the TiO 2 thin film, the crystals nucleated from the thin films was homogeneous and the average crystalline sizes were 35 nm. The transmittance spectra of the films revealed transparency in the visible region of the spectrum. SiO 2 /TiO 2 /SiO 2 thin film showed better hydrophilicity under irradiation and storage in comparison to SiO 2 /TiO 2 thin film. SiO 2 /TiO 2 /SiO 2 tri-layer thin film showed superhydrophilicity which greatly encourages the antifogging function of the film.

Materials research express, May 31, 2019

In this research, SiO2/SiO2–TiO2 thin films were coated on polycarbonate (PC) slides. Thin films ... more In this research, SiO2/SiO2–TiO2 thin films were coated on polycarbonate (PC) slides. Thin films were characterized by FTIR, FE-SEM, UV–vis-NIR spectrophotometer, and water contact angle (WCA) analyzer. To study the photoinduced superhydrophilicity, the prepared thin films were irradiated by UV light in different period of times and then WCA was measured. Besides, the adhesion, hardness, self-cleaning property and antifogging ability of the thin films were examined. The results specified that the creation of the SiO2/SiO2–TiO2 two layers enhanced the hardness and transmittance of the PC slide. Indeed, PC coated SiO2/SiO2–TiO2 two layers displays photoinduced superhydrophilicity (CA, 5° after UV irradiated), and it is very effectual at eliminating fog and dirt overflowing of water drops.

Materials research express, Apr 5, 2019