Zahra Rezvani; Mazaher Gholipourmalekabadi; Saeid Kargozar; Peiman Brouki Milan; Masoud Mozafari
Abstract
In this study, organic montmorillonite (OMMT) is a modified form of montmorillonite (MMT) in which chitosan (CS) intercalated MMT by ion exchange of sodium ions from Na/MMT with –NH3 + of CS. The structural analysis confirmed intercalation of CS into MMT layers, indicating that CS molecular chains ...
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In this study, organic montmorillonite (OMMT) is a modified form of montmorillonite (MMT) in which chitosan (CS) intercalated MMT by ion exchange of sodium ions from Na/MMT with –NH3 + of CS. The structural analysis confirmed intercalation of CS into MMT layers, indicating that CS molecular chains incorporated into the MMT layers. The interlayer distance of the MMT layered was 1.128nm and in the OMMT layers enlarged to 2.365 nm. Antibacterial activity analysis showed that unmodified MMT could not inhibit the growth of bacteria. Nevertheless, after addition of the CS molecules, an increase in the interlayer distance of MMT was observed. No difference was observed between the viability of the human dental pulp stem cells (hDPSCs) contacted to different concentrations (ranging from 0.5 to 2mg/ml) of MMT and OMMT in all time intervals, when compared with the control samples. Furthermore, neither MMT nor OMMT showed apoptosis and cytotoxicity effect on the cells. The strong antibacterial activity of the synthesized OMMT nanocomposite was also confirmed against E. coli, S. aureus, K. pneumonia and P. aeruginosa, suggesting its high potential for the prevention of post-surgical infections.
S. Subbarayudu; V. Madhavi;S. Uthanna
Abstract
MoO3 films were deposited on Corning glass and silicon substrates held at room temperature (303 K) by RF magnetron sputtering of metallic molybdenum target at a fixed oxygen partial pressure of 4x10 -4 mbar and sputter pressure of 4x10 -2 mbar. The as deposited films were annealed in air at different ...
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MoO3 films were deposited on Corning glass and silicon substrates held at room temperature (303 K) by RF magnetron sputtering of metallic molybdenum target at a fixed oxygen partial pressure of 4x10 -4 mbar and sputter pressure of 4x10 -2 mbar. The as deposited films were annealed in air at different temperatures in the range 473 – 673 K. X-ray diffraction studies suggest that the as-deposited and the films annealed at 473 K were amorphous in nature, while those annealed at 573 and 673 K were polycrystalline with mixed phases of α- orthorhombic and β- monoclinic MoO3. Scanning electron microscope images of the films annealed at 573 and 673 K exhibited nanoflower like and nanodisk like structures due to improvement in the crystallinity. Fourier transform infrared studies showed the characteristic vibrations of MoO3 with shift in the vibrational modes of Mo = O and Mo – O – Mo with increase of annealing temperature. The optical absorption edge of the films shifted towards lower wavelengths side with increase of annealing temperature. Optical band gap of as-deposited films was 2.98 eV with refractive index 2.01, while those annealed at 673 K showed the optical band gap of 3.15 eV and refractive index of 2.08. The MoO3 films annealed at 673 K were of nanocrystalline with crystallite size of 39 nm with optical band gap of 3.15 eV and refractive index of 2.08 were favorable for electron blocking and hole-selective layers in bulk-heterojuction solar cells.
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