Optical characterizations of PMMA/metal oxide nanoparticles thin films: bandgap engineering using a novel derived model.

A novel optical model of the experimental transmission spectra of nanocomposite PVC-PS hybrid thin films doped with silica nanoparticles.

This article reports a solution-processed synthesis of copper oxide (CuxO) to be used as a potential photocathode for solar hydrogen production in the solar water-splitting system. CuxO thin films ...

Solution-Processed Synthesis of Copper Oxide (CuxO) Thin Films for Efficient Photocatalytic Solar Water Splitting

This work describes an environmental-friendly preparation of ZnO nanoparticles using aqueous oat extract. The advanced electrochemical and optical features of green synthesized ZnONPs displayed excellent antibacterial activity and exhibited an important role in pharmaceutical determinations. The formation of nanoscale ZnO was confirmed using various spectroscopic and microscopic investigations. The formed nanoparticles were found to be around 100 nm. The as-prepared ZnONPs were monitored for their antibacterial potential against different bacterial strains. The inhibition zones for ZnONPs were found as Escherichia coli (16 mm), Pseudomonas aeruginosa (17 mm), Staphylococcus aureus (12 mm) and Bacillus subtilis (11 mm) using a 30-µg mL−1 sample concentration. In addition, ZnONPs exhibited significant antioxidant effects, from 58 to 67%, with an average IC50 value of 0.88 ± 0.03 scavenging activity and from 53 to 71% (IC50 value of 0.73 ± 0.05) versus the scavenging free radicals DPPH and ABTS, respectively. The photocatalytic potential of ZnONPs for Rhodamine B dye degradation under UV irradiation was calculated. The photodegradation process was carried out as a function of time-dependent and complete degradation (nearly 98%), with color removal after 120 min. Conclusively, the synthesized ZnONPs using oat biomass might provide a great promise in the future for biomedical applications.

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Multifunctional Eco-Friendly Synthesis of ZnO Nanoparticles in Biomedical Applications

In this work, we reported a new insight on the kinetics of photoisomerization and time evolution of hybrid thin films considering the azo-dye methyl red (MR) incorporated with graphene accommodated in polyethylene oxide (PEO). The kinetics of photoisomerization and time-evolution of hybrid thin films were investigated using UV-Vis s and FTIR spectroscopies, as well as appropriate models developed with new analytical methods. The existence of azo-dye MR in the complex is crucial for the resource action of the trans cis cycles through UV-illumination Visible-illumination relaxations. The results of the UV-Vis and the FTIR investigations prove the cyclical trans [...]&nbsp.

New Insight on Photoisomerization Kinetics of Photo-Switchable Thin Films Based on Azobenzene/Graphene Hybrid Additives in Polyethylene Oxide.

Hybrid material of poly-methyle-methacrylate (PMMA)-benzyl-dimethyl-ketal-azo dye methyl red (MR) thin film composites doped by various concentrations of ZnO NPs have been dip coated on glass substrates. The existence of azo dye (MR) in the composite was intentional to give the solution the desired pH level and to induce the cis ↔ trans cycles through illumination ↔ thermal relaxation. The optical and structural properties of the as-prepared thin films are investigated in relevance to ZnO NPs contents and the period of UV light illumination (short- and long-wavelength UV light). We found that the PMMA-BDK-MR doped by 1% ZnO NPs could be successfully used in optical data storage by implementing this composite in the WRITE/READ/ERASE cycle repeatedly. Specifically, it was found that the absorption band of the PMMA-BDK-MR doped by 1% ZnO NPs thin film lies between 350 and 600 nm upon illumination with 366 nm UV light for 10 s. Thermogravimetric analysis (TGA) was used to investigate the thermal stability of PMMA-BDK-MR/ZnO NPs. The TGA results are presented and interpreted. Furthermore, we investigated annealed poly-methyle-methacrylate-benzyl-dimethyl-ketal-methyl-red (PMMA-BDK-MR) doped by 1% ZnO NPs thin films. The trans–cis cycle has been repeated sequentially to confirm the hysteresis behavior for possible data READ/WRITE or ERASE memory applications.

Synthesis and characterization of ZnO NPs-doped PMMA-BDK-MR polymer-coated thin films with UV curing for optical data storage applications

Polyethylene oxide (PEO) complexed with molecular iodine (I2) forming PEO/I2 complex composites stand‐free films were investigated using dielectric relaxation, X-ray photoelectron spectroscopy (XPS), UV–Vis spectrophotometry, structural and morphological techniques. Scanning electron microscopy was used to monitor the variation in the surface morphology and the related roughness. 2D Energy-dispersive X-ray spectroscopy (EDX) measurements enabled to observe the distribution of iodine on the film surface. High resolution XPS measurements were used to define the iodine anion types and the metallic iodine existence, as well as the relevant concentrations based on the binding energies. The dielectric relaxation measurements were carried out over the frequency range from 0.1 to 107 Hz and temperature range from 155 to 330 K. Dielectric loss (e′′) curves were fitted to the Havriliak–Negami (HN) model for one and/or two relaxation peaks (α and β), with and without the electrical conductivity contribution term, in order to deduce the relaxation time (τ) and the dielectric strengths (Δe), in addition to the electrical conductivities (σ). The temperature-dependent data of β- and σ- relaxations follow the law of Arrhenius thermal activation indicating the presence of typical glass-forming polymers. Δe of α-relaxation obeys the curvature pattern of Vogel-Tammann-Fulcher (VTF) thermal activation law. The electrical conductivity of the system increases 6000 folds by doping PEO with 5 wt% of iodine at the same temperature (293 K).

Kholoud A. Al-Izzy

Papers

Synthesis and characterization of ZnO NPs-doped PMMA-BDK-MR polymer-coated thin films with UV curing for optical data storage applications

Dielectric relaxation, XPS and structural studies of polyethylene oxide/iodine complex composite films