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El-Aassar M.R.,Advanced Technology and New Material Institute | El Fawal G.F.,Advanced Technology and New Material Institute | Kamoun E.A.,Advanced Technology and New Material Institute | Fouda M.M.G.,King Saud University | Fouda M.M.G.,National Research Center of Egypt
International Journal of Biological Macromolecules | Year: 2015

In this work, hydrogel membrane composed of; kappa carrageenan (κC) and hyaluronic acid (HA) crosslinked with epichlorohydrine is produced. The optimum condition has been established based on their water absorption properties. Tensile strength (TS) and elongation (. E%) for the formed films are evaluated. The obtained films were characterized by FTIR, scanning electron microscopy (SEM) and thermal analysis. All membranes were loaded with l-carnosine as a drug model. The swelling properties and kinetics of the release of the model drug from the crosslinked hydrogel membrane were monitored in buffer medium at 37. °C. The equilibrium swelling of films showed fair dependency on the high presence of HA in the hydrogel. Moreover, the cumulative release profile increased significantly and ranged from 28% to 93%, as HA increases. SEM explored that, the porosity increased by increasing HA content; consequently, drug release into the pores and channels of the membranes is facilitated. In addition, water uptake % increased as well. A slight change in TS occurred by increasing the HA% to κC, while the highest value of strain for κC membrane was 498.38% by using 3% HA. The thermal stability of the κC/HA was higher than that of HA. © 2015 Elsevier B.V. Source


Farag A.A.M.,Ain Shams University | Farag A.A.M.,Al Jouf University | Abdel Rafea M.,Advanced Technology and New Material Institute | Abdel Rafea M.,Imam Muhammad ibn Saud Islamic University | And 3 more authors.
Journal of Alloys and Compounds | Year: 2015

Low cost dip coating technique was successfully used to deposit highly uniform and good adhesive nanocrystalline Zn1-xCdxS (0 ≤ x ≤ 0.9) thin films. The surface morphology and crystalline structural characteristics of Zn1-xCdxS were achieved by using atomic force microscopy (AFM) and transmission electron microscopy (TEM), respectively. Transmission spectra show red shifting of absorption edge as the Cd content increased. The optical constants were accurately determined by using reflectance and transmittance spectra. The effect of Cd-content on refractive index, extinction index and other optical dispersion parameters were also investigated. The dispersion of the refractive index was discussed in terms of single oscillator model. In addition, the ratio of free carrier concentration to its effective mass was estimated. The calculated value of oscillator energy Eo obeys the empirical relation (Eo ≈ 2 Eg), obtained from single oscillator model. Small magnitude of optical electronegativity (χ∗) for Zn1-xCdxS (0 ≤ x ≤ 0.9) thin films and relatively high refractive index can be attributed to covalent nature, in agreement with β value, obtained from dispersion energy analysis. Moreover, molar polarizability and third-order nonlinear optical susceptibility were also considered. © 2014 Elsevier B.V. All rights reserved. Source


Ibrahim M.A.,Ain Shams University | Farag A.A.M.,Ain Shams University | Farag A.A.M.,Al Jouf University | Roushdy N.,Advanced Technology and New Material Institute | El-Gohary N.M.,Ain Shams University
Optical Materials | Year: 2016

Friedländer condensation of 2-amino-6-chlorochromone-3-carboxaldehyde (1) with 4-hydroxycoumarin (2) under basic conditions afforded 10-chloro-6H,8H-dichromeno[2,3-b:3′,4′-e]pyridine-6,8-dione (3) (CDPD). Structure of CDPD was deduced based on its correct elemental analysis and spectral data (IR, 1H NMR, 13C NMR and mass spectra). Crystalline structure by using X-ray diffraction confirms a polycrystalline nature of the powder and films with monoclinic system. A flower-like morphology was resolved for the high magnification images of scanning electron microscopy. Three direct optical band gaps were obtained and found to be 1.17, 2.24 and 3.40 eV, respectively. A sharp single peak of photoluminescence in the visible region was observed and centered at around 683 nm as well as another two peaks at 417 and 386 nm. Rectification characteristics of the device based CDPD indicates that the device behaves as a diode. A maximum value of photosensitivity of the device was obtained under effect of 60 mW/cm2 and bias voltage of 1.25 V. The phototransient characteristics of the device confirm that the device can be operated as a photodiode. © 2015 Elsevier B.V. All rights reserved. Source


El-Shazly O.,Alexandria University | Farag A.A.M.,University of Science and Arts of Iran | Farag A.A.M.,Ain Shams University | Rafea M.A.,Islamic University | And 3 more authors.
Sensors and Actuators, A: Physical | Year: 2016

Nanocrystalline Zn1-xCdxS (0 ≤ x ≤ 0.9) thin films were synthesized by low cost dip coating technique for optoelectronic application. Optical absorption characteristics of the prepared films were investigated by spectrophotometric measurements and the values of the optical band gap and Urbach energy were determined. The optical absorption measurements indicate that the absorption mechanism is due to allowed direct transitions and Urbach energy values changes with Cd-content. Quantum confinement in strained films with various Cd content values was investigated and the optical results showed that the average diameter of nanoparticles ranges from 5.7 nm to 14.5 nm. Values of the absorption edge were found to shift toward the higher wavelength region and hence the direct band gap energy varies from 4.00 eV for the ZnS film and 2.55 eV for the Zn0.1Cd0.9S film. A light scattering model of the films was explained by the simplest model on the basis of Rayleigh scattering theory. Heterojunctions of Zn1-xCdxS (0 ≤ x ≤ 0.9)/p-Si showed photovoltaic and photosensing characteristics depending on the Cd-content. The main photovoltaic parameters were investigated as a function of Cd content under illumination of 100 mW/cm2. © 2016 Elsevier B.V. All rights reserved. Source


Ibrahim M.A.,Ain Shams University | Farag A.A.M.,University of Science and Arts of Iran | Farag A.A.M.,Ain Shams University | Roushdy N.,Advanced Technology and New Material Institute | El-Gohary N.M.,Ain Shams University
Journal of Molecular Structure | Year: 2016

Condensation reaction of 6-bromochromone-3-carboxaldehyde (1) with dimedone afforded 9-(6-bromo-4-oxo-4H-chromen-3-yl)-3,4,6,7-tetrahydro-3,3,6,6-tetramethyl-2H-xanthene-1,8-(5H,9H)-dione (3, BOCTTX). Structure of BOCTTX was deduced based on its correct elemental analysis and spectral data (IR, 1H NMR, 13C NMR and mass spectra). Thin films of BOCTTX were prepared in this study by using spin coating technique. X-ray diffraction, scanning electron microscope analysis were studied for study the crystal and morphology characterization of BOCTTX. The results indicate that BOCTTX has a polycrystalline nature with monoclinic structure. From differential scanning calorimetry, BOCTTX is found to be thermally stable up to 583 K and the chemical structure plays an important role in the thermal decomposition process. The optical absorption of the film was studied in the UV-Vis spectral range and the value of two allowed energy gaps of 2.2 and 3.3 eV. Current-voltage characteristics of BOCTTX based devices were studied in dark and under various illumination intensities in the range 20-100 mW/cm2. Electrical and photoelectrical parameters were studied as a function of light intensity. The obtained results exhibits photoconductivity cauterization and suggest that the diode can be used as a photodiode in optoelectronic sensor application. © 2015 Elsevier B.V. All rights reserved. Source

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