Free volume dependence on electrical properties of Poly (styrene co-acrylonitrile)/Nickel oxide polymer nanocomposites

New and efficient NiO/chitosan/polyvinyl alcohol nanocomposites as antibacterial and dye adsorptive films

The development of composite films with enhanced antibacterial and dye decolorization properties for water treatment has attracted a great attention. In this study, nickel oxide/chitosan/polyvinyl alcohol nanocomposite films containing different weight percentage of NiO nanoparticles with a dual functionality, removal of toxic dye and antibacterial properties, were prepared. Methyl orange (MO) was selected as a target pollutant. Additionally, the antimicrobial activity of the films against two Gram positive bacteria (Staphylococcus aureus and Bacillus cereus) and two Gram negative bacteria (Escherichia coli and Salmonella Typhimurium) was studied. The prepared samples were characterized by XRD, HRTEM, FESEM, ATR-FTIR, UV-Vis spectroscopy, and dielectric measurements. The morphological examination proved that the nanocomposite film has more porous structure compared to the unmodified chitosan/PVA. The antimicrobial tests indicated that the modified chitosan/PVA films have higher activity than pure chitosan/PVA toward all the tested pathogenic bacteria. The impact of the NiO amount (0.5, 1.5, 3, and 5 wt%), contact time (0-150 min), and adsorbent dose (40, 80, and 100 mg) on the removal of MO was studied. Dye adsorption results proved that the incorporation of 5 wt% NiO led to more than 2 fold increase in the dye removal percentage in comparison with the unmodified PVA/chitosan film.

Surface Carbon Shell-Functionalized ZrO2 as Nanofiller in Polymer Gel Electrolyte-Based Dye-Sensitized Solar Cells

We prepare dye-sensitized solar cells (DSSCs) fabricated with a poly (ethylene glycol) based polymer gel electrolytes (PGEs) incorporating surface carbon shell-functionalized ZrO2 nanoparticles (ZrO2-C) as nanofillers (NFs). ZrO2 are polymerized via atom transfer radical polymerization (ATRP) using poly (ethylene glycol) methyl ether methacrylate (POEM) as a scaffold to prepare the ZrO2-C through carbonization. The power conversion efficiency of DSSC with 12 wt% ZrO2-C/PGEs is 5.6%, exceeding that with PGEs (4.4%). The enhanced efficiency is attributed to Lewis acid-base interactions of ZrO2-C and poly (ethylene glycol), catalytic effect of the carbon shells of ZrO2-C, which results in reduced crystallinity, enhanced ion conductivity of electrolytes, decreased counterelectrode/electrolyte interfacial resistance, and improved charge transfer rate. These results demonstrate that ZrO2-C introduction to PGEs effectively improves the performance of DSSCs.