Abstract: Water contamination by toxic compound is one of the serious environmental problems today. These toxic compounds mostly originated from industrial effluents, agriculture, natural sources and human waste. These studies focus on modification of multiwalled carbon nanotube (MWCNTs) with nanoparticle of calixarene and explore the possibility of using this modification for the remediation of cadmium in water. The nanocomposites were prepared by dissolving calixarene in chloroform solution as solvent, followed by additional multiwalled carbon nanotube (MWCNTs) then sonication process for 3 hour and fabricated the nanocomposites on substrate by spin coating method. Finally, the nanocomposites were tested on cadmium ion (10 mg/ml). The morphology of nanocomposites was investigated by FESEM showing the formation of calixarene on the outer walls of carbon nanotube and cadmium ion also clearly seen from the micrograph. This formation was supported by using energy dispersive x-ray (EDX). The presence of cadmium ions in the films, leads to some changes in the surface potential and Fourier Transform Infrared spectroscopy (FTIR).The nanocomposites MWCNTs-calixarene have potential for development of sensor for pollutant monitoring and nanoelectronics devices applications.
Abstract: A new method for determining the distribution of
birefringence and linear dichroism in optical polymer materials is
presented. The method is based on the use of polarizationholographic
diffraction grating that forms an orthogonal circular basis
in the process of diffraction of probing laser beam on the grating. The
intensities ratio of the orders of diffraction on this grating enables the
value of birefringence and linear dichroism in the sample to be
determined. The distribution of birefringence in the sample is
determined by scanning with a circularly polarized beam with a
wavelength far from the absorption band of the material. If the
scanning is carried out by probing beam with the wavelength near to
a maximum of the absorption band of the chromophore then the
distribution of linear dichroism can be determined. An appropriate
theoretical model of this method is presented. A laboratory setup was
created for the proposed method. An optical scheme of the laboratory
setup is presented. The results of measurement in polymer films with
two-dimensional gradient distribution of birefringence and linear
dichroism are discussed.
Abstract: The effect of the inclusion of thyme and rosemary
essential oils into chitosan films, as well as the microbiological and
physical properties when storing chitosan film with and without the
mentioned inclusion was studied. The film forming solution was
prepared by dissolving chitosan (2%, w/v), polysorbate 80 (4% w/w
CH) and glycerol (16% w/w CH) in aqueous lactic acid solutions
(control). The thyme (TEO) and rosemary (REO) essential oils (EOs)
were included 1:1 w/w (EOs:CH) on their combination 50/50
(TEO:REO). The films were stored at temperatures of 5, 20, 33°C
and a relative humidity of 75% during four weeks. The films with
essential oil inclusion did not show an antimicrobial activity against
strains. This behavior could be explained because the chitosan only
inhibits the growth of microorganisms in direct contact with the
active sites. However, the inhibition capacity of TEO was higher than
the REO and a synergic effect between TEO:REO was found for S.
enteritidis strains in the chitosan solution.
Some physical properties were modified by the inclusion of
essential oils. The addition of essential oils does not affect the
mechanical properties (tensile strength, elongation at break, puncture
deformation), the water solubility, the swelling index nor the DSC
behavior. However, the essential oil inclusion can significantly
decrease the thickness, the moisture content, and the L* value of
films whereas the b* value increased due to molecular interactions
between the polymeric matrix, the loosing of the structure, and the
chemical modifications. On the other hand, the temperature and time
of storage changed some physical properties on the chitosan films.
This could have occurred because of chemical changes, such as
swelling in the presence of high humidity air and the reacetylation of
amino groups. In the majority of cases, properties such as moisture
content, tensile strength, elongation at break, puncture deformation,
a*, b*, chrome, 7E increased whereas water resistance, swelling
index, L*, and hue angle decreased.
Abstract: In view of a possible application in optical data
storage devices, diffraction grating efficiency of an organic dye, Acid
Fuchsin doped in PMMA matrix was studied under excitation with
CW diode pumped Nd: YAG laser at 532 nm. The open aperture Zscan
of dye doped polymer displayed saturable absorption and the
closed aperture Z-scan of the samples exhibited negative
nonlinearity. The diffraction efficiency of the grating is the ratio of
the intensity of the first order diffracted power to the incident read
beam power. The dye doped polymer films were found to be good
media for recording. It is observed that the formation of gratings
strongly depend on the concentration of dye in the polymer film, the
intensity ratios of the writing beams and the angle between the
writing beams. It has been found that efficient writing can be made at
an angle of 20o and when the intensity ratio of the writing beams is
unity.
Abstract: Replacement of plastics used in the food industry
seems to be a serious issue to overcome mainly the environmental
problems in recent years. This study investigates the hydrophilicity
and permeability properties of starch biopolymer which ethylene
vinyl alcohol (EVOH) (0-10%) and nanocrystalline cellulose (NCC)
(1-15%) were used to enhance its properties. Starch -EVOH
nanocomposites were prepared by casting method in different
formulations. NCC production by acid hydrolysis was confirmed by
scanning electron microscopy. Solubility, water vapor permeability,
water vapor transmission rate and moisture absorbance were
measured on each of the nanocomposites. The results were analyzed
by SAS software. The lowest moisture absorbance was measured in
pure starch nanocomposite containing 8% NCC. The lowest
permeability to water vapor belongs to starch nanocomposite
containing 8% NCC and the sample containing 7.8% EVOH and 13%
NCC. Also the lowest solubility was observed in the composite
contains the highest amount of EVOH. Applied Process resulted in
production of bio films which have good resistance to water vapor
permeability and solubility in water. The use of NCC and EVOH
leads to reduced moisture absorbance property of the biofilms.
Abstract: TiO2 thin films have been prepared by the sol-gel dipcoating
technique in order to elaborate antireflective thin films for
monocrystalline silicon (mono-Si). The titanium isopropoxyde was
chosen as a precursor with hydrochloric acid as a catalyser for
preparing a stable solution. The optical properties have been tailored
with varying the solution concentration, the withdrawn speed, and the
heat-treatment. We showed that using a TiO2 single layer with 64.5
nm in thickness, heat-treated at 450°C or 300°C reduces the mono-Si
reflection at a level lower than 3% over the broadband spectral
domains [669-834] nm and [786-1006] nm respectively. Those latter
performances are similar to the ones obtained with double layers of
low and high refractive index glasses respectively.
Abstract: Yttrium oxide (Y2O3) films have been successfully
deposited with yttrium-ethylenediamine tetraacetic acid (EDTA·Y·H)
complexes prepared by various milling techniques. The effects of the
properties of the EDTA·Y·H complex on the properties of the
deposited Y2O3 films have been analyzed. Seven different types of the
raw EDTA·Y·H complexes were prepared by various commercial
milling techniques such as ball milling, hammer milling, commercial
milling, and mortar milling. The milled EDTA·Y·H complexes
exhibited various particle sizes and distributions, depending on the
milling method. Furthermore, we analyzed the crystal structure,
morphology and elemental distribution profile of the metal oxide films
deposited on stainless steel substrate with the milled EDTA·Y·H
complexes. Depending on the milling technique, the flow properties of
the raw powders differed. The X-ray diffraction pattern of all the
samples revealed the formation of Y2O3 crystalline phase, irrespective
of the milling technique. Of all the different milling techniques, the
hammer milling technique is considered suitable for fabricating dense
Y2O3 films.
Abstract: The hydrogenated amorphous carbon films (α-C:H)
were deposited on p-type Si (100) substrates at different thicknesses by
radio frequency plasma enhanced chemical vapor deposition
technique (rf-PECVD). Raman spectra display asymmetric
diamond-like carbon (DLC) peaks, representative of the α-C:H films.
The decrease of intensity ID/IG ratios revealed the sp3 content arise at
different thicknesses of the α-C:H films. In terms of mechanical
properties, the high hardness and elastic modulus values showed the
elastic and plastic deformation behaviors related to sp3 content in
amorphous carbon films. Electrochemical properties showed that the
α-C:H films exhibited excellent corrosion resistance in air-saturated
3.5 wt.% NaCl solution for pH 2 at room temperature. Thickness
increasing affected the small sp2 clusters in matrix, restricting the
velocity transfer and exchange of electrons. The deposited α-C:H films
exhibited excellent mechanical properties and corrosion resistance.
Abstract: Hydrogenated amorphous carbon (a-C:H) films have
been synthesized by a radio frequency plasma enhanced chemical
vapor deposition (rf-PECVD) technique with different bias voltage
from 0.0 to -0.5 kV. The Raman spectra displayed the polymer-like
hydrogenated amorphous carbon (PLCH) film with 0.0 to -0.1 and
a-C:H films with -0.2 to -0.5 kV of bias voltages. The surface chemical
information of all films were studied by X-ray photoelectron
spectroscopy (XPS) technique, presented to C-C (sp2 and sp3) and C-O
bonds, and relative carbon (C) and oxygen (O) atomics contents. The
O contamination had affected on structure and optical properties. The
true density of PLCH and a-C:H films were characterized by X-ray
refractivity (XRR) method, showed the result as in the range of
1.16-1.73 g/cm3 that depending on an increasing of bias voltage. The
hardness was proportional to the true density of films. In addition, the
optical properties i.e. refractive index (n) and extinction coefficient (k)
of these films were determined by a spectroscopic ellipsometry (SE)
method that give formation to in 1.62-2.10 (n) and 0.04-0.15 (k)
respectively. These results indicated that the optical properties
confirmed the Raman results as presenting the structure changed with
applied bias voltage increased.
Abstract: Concerns on corrosion and effective coating
protection of double hull tankers and bulk carriers in service have
been raised especially in water ballast tanks (WBTs). Test
protocols/methodologies specifically that which is incorporated in the
International Maritime Organisation (IMO), Performance Standard
for Protective Coatings for Dedicated Sea Water ballast tanks (PSPC)
are being used to assess and evaluate the performance of the coatings
for type approval prior to their application in WBTs. However, some
of the type approved coatings may be applied as very thick films to
less than ideally prepared steel substrates in the WBT. As such films
experience hygrothermal cycling from operating and environmental
conditions, they become embrittled which may ultimately result in
cracking. This embrittlement of the coatings is identified as an
undesirable feature in the PSPC but is not mentioned in the test
protocols within it. There is therefore renewed industrial research
aimed at understanding this issue in order to eliminate cracking and
achieve the intended coating lifespan of 15 years in good condition.
This paper will critically review test protocols currently used for
assessing and evaluating coating performance, particularly the IMO
PSPC.
Abstract: Poly(lactic acid) (PLA) is a biodegradable polymer
which has good mechanical properties, however, its brittleness limits
its usage especially in packaging materials. Therefore, in this work,
PLA based polyurethane films were prepared by synthesizing with
different types of isocyanates; methylene diisocyanate (MDI) and
hexamethylene diisocyanates (HDI). For this purpose, PLA based
polyurethane must have good strength and flexibility. Therefore,
polycaprolactone which has better flexibility were prepared with
PLA. An effective way to endow polylactic acid with toughness is
through chain-extension reaction of the polylactic acid pre-polymer
with polycaprolactone used as chain extender. Polyurethane prepared
from MDI showed brittle behaviour, while, polyurethane prepared
from HDI showed flexibility at same concentrations.
Abstract: Single-phase, high band gap energy Zn0.5Mg0.5O films were grown under oxygen pressure, using pulse laser deposition with a Zn0.5Mg0.5O target. Structural characterization studies revealed that the crystal structures of the ZnX-1MgXO films could be controlled via changes in the oxygen pressure. TEM analysis showed that the thickness of the deposited Zn1-xMgxO thin films was 50–75 nm. As the oxygen pressure increased, we found that one axis of the crystals did not show a very significant increase in the crystallization compared with that observed at low oxygen pressure. The X-ray diffraction peak intensity for the hexagonal-ZnMgO (002) plane increased relative to that for the cubic-ZnMgO (111) plane. The corresponding c-axis of the h-ZnMgO lattice constant increased from 5.141 to 5.148 Å, and the a-axis of the c-ZnMgO lattice constant decreased from 4.255 to 4.250 Å. EDX analysis showed that the Mg content in the mixed-phase ZnMgO films decreased significantly, from 54.25 to 46.96 at.%. As the oxygen pressure was increased from 100 to 150 mTorr, the absorption edge red-shifted from 3.96 to 3.81 eV; however, a film grown at the highest oxygen pressure tested here (200 mTorr).
Abstract: In this study, we developed a complementary electrochromic device consisting of WO3 and NiO films fabricated by rf-magnetron sputtered. The electrochromic properties of WO3 and NiO films were investigated using cyclic voltammograms (CV), performed on WO3 and NiO films immersed in an electrolyte of 1 M LiClO4 in propylene carbonate (PC). Optical and electrochemical of the films, as a function of coloration–bleaching cycle, were characterized using an UV-Vis-NIR spectrophotometer and cyclic voltammetry (CV). After investigating the properties of WO3 film, NiO film, and complementary electrochromic devices, we concluded that this device provides good reversibility, low power consumption of -2.5 V in color state, high variation of transmittance of 58.96%, changes in optical density of 0.81 and good memory effect under open-circuit conditions. In addition, electrochromic component penetration rate can be retained below 20% within 24h, showing preferred memory features; however, component coloring and bleaching response time are about 33s.
Abstract: In this study, the Mo-electrode thin films were deposited using two-stepped process and the high purity copper indium selenide-based powder (CuInSe2, CIS) was fabricated by using hydrothermal process by Nanowin Technology Co. Ltd. Because the CIS powder was aggregated into microscale particles, the CIS power was ground into nano-scale particles. 6 wt% CIS particles were mixed and dispersed into isopropyl alcohol (IPA). A new non-vacuum thin-film deposition process, spray coating method (SPM), was investigated to deposit the high-densified CIS absorber layers. 0.1 ml CIS solution was sprayed on the 20 mm×10 mm Mo/glass substrates and then the CuInSe2 thin films were annealed in a selenization furnace using N2 as atmosphere. The annealing temperature and time were set at 550oC and 5 min, and 0.0g~0.6g extra Se content was added in the furnace. The influences of extra Se content on the densification, crystallization, resistivity (ρ), hall mobility (μ), and carrier concentration of the CIS absorber layers were well investigated in this study.
Abstract: In this study, we investigated (In,Ga,Zn)Ox (IGZO) thin films and examined their characteristics of using Ga2O3-2 ZnO (GZO) co-sputtered In2O3 prepared by dual target radio frequency magnetron sputtering at room temperature in a pure Ar atmosphere. RF powers of 80 W and 70 W were used for GZO and pure In2O3, room temperature (RT) was used as deposition temperature, and the deposition time was changed from 15 min to 60 min. Structural, surface, electrical, and optical properties of IGZO thin films were investigated as a function of deposition time. Furthermore, the GZO co-sputtered In2O3 thin films showed a very smooth and featureless surface and an amorphous structure regardless of the deposition time due to the room temperature sputtering process. We would show that the co-sputtered IGZO thin films exhibited transparent electrode properties with high transmittance ratio and low resistivity.
Abstract: This work details the generation of thin films of
structured zeolite catalysts (ZSM–5 and Y) onto the surface of a
metal substrate (FeCrAlloy) using in-situ hydrothermal synthesis. In
addition, the zeolite Y is post-synthetically modified by acidified
ammonium ion exchange to generate US-Y. Finally the catalytic
activity of the structured ZSM-5 catalyst films (Si/Al = 11, thickness
146 0m) and structured US–Y catalyst film (Si/Al = 8, thickness
230m) were compared with the pelleted powder form of ZSM–5 and
USY catalysts of similar Si/Al ratios.
The structured catalyst films have been characterised using a range
of techniques, including X-ray diffraction (XRD), Electron
microscopy (SEM), Energy Dispersive X–ray analysis (EDX) and
Thermogravimetric Analysis (TGA). The transition from oxide-onalloy
wires to hydrothermally synthesised uniformly zeolite coated
surfaces was followed using SEM and XRD. In addition, the
robustness of the prepared coating was confirmed by subjecting these
to thermal cycling (ambient to 550oC).
The cracking of n–heptane over the pellets and structured catalysts
for both ZSM–5 and Y zeolite showed very similar product
selectivities for similar amounts of catalyst with an apparent
activation energy of around 60 kJ mol-1. This paper demonstrates that
structured catalysts can be manufactured with excellent zeolite
adherence and when suitably activated/modified give comparable
cracking results to the pelleted powder forms. These structured
catalysts will improve temperature distribution in highly exothermic
and endothermic catalysed processes.
Abstract: RF magnetron sputtering is used on the ceramic targets, each of which contains zinc oxide (ZnO), zinc oxide doped with aluminum (AZO) and zinc oxide doped with gallium (GZO). The electric conduction mechanism of the AZO and GZO films came mainly from the Al and Ga, the oxygen vacancies, Zn interstitial atoms, and Al and/or Ga interstitial atoms. AZO and GZO films achieved higher conduction than did ZnO film, it being ion vacant and nonstoichiometric. The XRD analysis showed a preferred orientation along the (002) plane for ZnO, AZO, and GZO films.
Abstract: Microfibrous palygorskite and tubular halloysite clay mineral combined with nanocrystalline TiO2 are incorporating in the preparation of nanocomposite films on glass substrates via sol-gel route at 450oC. The synthesis is employing nonionic surfactant molecule as pore directing agent along with acetic acid-based sol-gel route without addition of water molecules. Drying and thermal treatment of composite films ensure elimination of organic material lead to the formation of TiO2 nanoparticles homogeneously distributed on the palygorskite or halloysite surfaces. Nanocomposite films without cracks of active anatase crystal phase on palygorskite and halloysite surfaces are characterized by microscopy techniques, UV-Vis spectroscopy, and porosimetry methods in order to examine their structural properties.
The composite palygorskite-TiO2 and halloysite-TiO2 films with variable quantities of palygorskite and halloysite were tested as photocatalysts in the photo-oxidation of Basic Blue 41 azo dye in water. These nanocomposite films proved to be most promising photocatalysts and highly effective to dye’s decoloration in spite of small amount of palygorskite-TiO2 or halloysite-TiO2 catalyst immobilized onto glass substrates mainly due to the high surface area and uniform distribution of TiO2 on clay minerals avoiding aggregation.
Abstract: A thin gold metal layer was deposited on the top of
silicon oxide films containing embedded Si nanocrystals (Si-nc). The
sample was annealed in a gas containing nitrogen, and subsequently
characterized by photoluminescence. We obtained 3-fold
enhancement of photon emission from the Si-nc embedded in silicon
dioxide covered with a Gold layer as compared with an uncovered
sample. We attribute this enhancement to the increase of the
spontaneous emission rate caused by the coupling of the Si-nc
emitters with the surface plasmons (SP). The evolution of PL
emission with laser irradiated time was also collected from covered
samples, and compared to that from uncovered samples. In an
uncovered sample, the PL intensity decreases with time,
approximately with two decay constants. Although the decrease of
the initial PL intensity associated with the increase of sample
temperature under CW pumping is still observed in samples covered
with a gold layer, this film significantly contributes to reduce the
permanent deterioration of the PL intensity. The resistance to
degradation of light-emitting silicon nanocrystals can be increased by
SP coupling to suppress the permanent deterioration. Controlling the
permanent photodeterioration can allow to perform a reliable optical
gain measurement.
Abstract: Cd1−xZnxS thins films have been fabricated from ZnS/CdS/ZnS multilayer thin film systems, by using the vacuum deposition method; the Rutherford backscattering (RBS) technique have been applied in order to determine the: structure, composition, depth profile, and stoichiometric of these films. The influence of the chemical and heat treatments on the produced films also have been investigated; the RBS spectra of the films showed that homogenous Cd1−xZnxS can be synthesized with x=0.45.