Narrow Results

The recent progress in nanofiber research has demonstrated the potential for improving the physical properties of materials through the integration of graphene nanoplatelets (GNP). This study involves the synthesis and characterization of novel GNP-infused polyvinylpyrrolidone (PVP) electrospun nanofibers. The required precursor solution was prepared using dimethylformamide (DMF) as a solvent, and that included 1.5wt.% concentrations of GNP with 20 wt.% of PVP in 10mL of DMF solution. The investigation using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed the morphology of the fibers with the distribution of graphene nanoplatelets. The zeta potential analysis demonstrates that the GNP/PVP nanofibers exhibit significant stability across a wide pH range, particularly in highly acidic and basic conditions. The thermogravimetric analysis (TGA) analysis showed exceptional thermal stability, with minimal weight loss until 300–400${}^{\circ }$C. The degradation of the PVP matrix was observed beyond 400${}^{\circ }$C. The results of the study show that GNP/PVP nanofibers have significant potential for specific applications in thermal management and energy storage under controlled temperature conditions.

In this study, a silver nanowires (AgNWs)/nano-zinc oxide (ZnO)/polyvinylpyrrolidone (PVP) film is fabricated as an alternative to indium tin oxide transparent conductive films (TCFs). AgNWs are prepared by the polyol method with PVP as a dispersant to prevent Ag nanoparticles agglomeration during AgNWs formation. Nano-ZnO is synthesized using sol–gel method. AgNWs/ZnO/PVP TCFs are prepared using the electrostatic spinning and spin coating methods for comparison. It is found that the best PVP/AgNO₃ molar ratio is 3.5:1. FTIR and XRD analyses show that 500°C calcination leads to better crystallinity and purity of nano-ZnO. Four-point prober analysis indicates that the higher the AgNWs content, the lower the TCF sheet resistance. The best sheet resistance of AgNWs/ZnO/PVP TCF by the electrostatic spinning method is obtained as 81 $\mathrm{\Omega }$/sq, and the light transmittance is 85.3%. Moreover, in the 5-week stability test, the sheet resistance of the electrospun TCF increases by 6.17%, much lower than 24.9% of the spin coated TCF. It is verified that the elecrospun AgNWs/ZnO/PVP composite TCF is a promising alternative to the traditional ITO TCFs.

The inhibitive performance of two water soluble polymers–polyacrylamide (PA) and polyvinylpyrrolidone (PVP) on the corrosion behavior of aluminum alloy 3SR in HCl solution was investigated using weight loss, hydrogen evolution, and thermometric methods at 30–60°C. Results obtained indicate that both polymers inhibited acid-induced corrosion of aluminum at the temperatures studied. PVP was found to be a better corrosion inhibitor than PA. All measurements from the three techniques show that inhibition efficiencies increase with increase in inhibitor concentration and decrease with increase in temperature. This indicates that the inhibitive actions of the polymers were mainly due to adsorption. Adsorption of these inhibitors follows Temkin and El-Awady adsorption isotherm models. Kinetic/thermodynamic parameters (E_a, K_ads, ) of adsorption of the studied inhibitors reveal that the adsorption was physical in nature and spontaneous. Differences in inhibition efficiency of the two polymers could be linked to their differences in molecular structure.

Indium tin oxide (ITO) nanoparticles with In/Sn = 9:1 (at.%) were synthesized by chemical coprecipitation method in an aqueous solution. The coprecipitate prepared at room temperature showed the crystal structure of indium oxide in X-ray diffraction when it was annealed at the temperature above 300°C under air atmosphere. Reduction process was accomplished to improve the electrical property of ITO powder and it changed powder color from yellow to dark green. Green ITO powder with particle sizes in the range of 15–30 nm was well dispersed by an addition of polyvinylpyrrolidone in an aqueous solution. The dispersibility of ITO sol solution was detected with ζ-potential analyzer. Near-IR reflective film was prepared by spin coating method using ITO sol solution. Transmission electron microsopy (TEM) and energy dispersive X-ray spectrometer (EDS) were used to characterize morphology and composition of ITO nanoparticles. Near-IR (NIR) spectrometer was used to determine reflectance on the surface of ITO film in the NIR-radiation region.

The viscosity behavior of polyvinylpyrrolidone (PVP) has been determined at 25°C in mixed solvents comprising of water/dimethylformamide (DMF) and water /methanol (MeOH). Analysis of the data has considered the PVP as being both host and guest polymer in solution. The intrinsic viscosity of PVP in DMF is higher than in water and in MeOH, but also increases in a mixed solvent with high water content because of the effect of polymer-solvent interactions. It was also found that the intrinsic viscosity of PVP at finite concentration, [η_PVP]_c decreases with an increase in the concentration of PVP in solution. The viscosity behavior of PVP in a mixed solvent is affected by the concentration-dependent intermolecular excluded volume effect, which can be quantitatively expressed by the parameter, b_Y, which reflects the shrinkage of PVP chain coils, resulting in a decrease of [η_PVP]_c. The effect of temperature on the viscosity behavior of PVP in MeOH shows that the interaction parameter increases up to a maximum value, and then decreases after a certain temperature.

Porous poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) membranes were successfully prepared using dibutyl phthalate (DBP), polyvinylpyrrolidone (PVP-K30), polyethylene glycol 200 (PEG200) as templates. SEM was used to examine the morphology of the PVDF-HFP porous membranes. It was found that these membranes have an asymmetric structure and the blends of PVDF-HFP/DBP formed nanoporous membranes, whereas the blends of PVDF-HFP/PVP-K30 formed "sponge-like" and microporous membranes. Moreover, the average pore size and porosity was about 0.3 μm and 48.7%, respectively. The crystallinity, thermal stability and mechanical strength of membranes were characterized by XRD, DSC, TGA and stress-strain tests. The results showed that the membranes are α crystals with excellent thermal stability. It was an effective way to regulate pore size and morphology of the PVDF-HFP membranes.

The administration of photosensitizers and their biocompatibility is crucial to the success of photodynamic therapy treatment. Amongst the various strategies developed to administer photosensitizers of low water-solubility, the use of polyvinylpyrrolidone (PVP), an FDA-approved food additive, is emerging as extremely promising. Its effect on photodynamic outcome was compared to more classical formulation in DMSO and direct solubilization in water. The tetrakis (2-(2-(2-methoxyethoxy)ethoxy)ethoxy)-Zn(II) phthalocyanine chosen as the model photosensitizer for this study proved to be a powerful photosensitizer. Even if slightly less efficient than DMSO formulation, PVP formulation proved to work very well, with submicromolar IC₅₀ and IC₉₀ values against MDA-MB-231 human cancer cells.

In the present study, Ni/Fe nanoparticles were synthesized using bound micelles as a template and 3, 3^′, 4, 4^′-tetrachlorobiphenyl (PCB77) as the target contaminant. The dual bound micelles, which are composed of polyvinylpyrrolidone (PVP) and sodium dodecyl sulfate (SDS), were found to be superior to single-component templates for the dispersion of metallic ions and thus directed the synthesis of Ni/Fe nanoparticles with improved properties. After characterization of the different nanoparticles, it was found that the sustained effectiveness of PVP–SDS bound micelles afforded specialized structures with two gradations of Ni/Fe nanoparticles, correlating to more active sites and higher activity. The improved activity of the Ni/Fe nanoparticles was finally exhibited by the higher ratio (99.3% in 72 h) and efficiency (k_obs of 0.0674 h^-1) of PCB77 removal. Herein, the utilization of PVP–SDS bound micelles is proposed as a template for the improvement of iron-based nanoparticles and correlated research.

Uniform pompon-like Ru nanoparticles with an average diameter of 148 nm were readily synthesized by reducing RuCl₃ with triethylene glycol (TG) as both a reducing agent and a solvent in the presence of PVP by oil-bath heating at 170°C for 6 h. The as-prepared Ru nano-pompons were characterized by TEM, XRD, XPS and UV-vis absorption spectroscopy. The effects of some parameters such as the average molecular weight and the concentration of PVP on the synthesis of Ru nano-pompons were investigated.

In our study, we successfully demonstrated bipolar resistive switching in Resistive Random-Access Memory (RRAM) devices using MAPbI${}_{3-}$${}_x$Cl${}_x$ mixed halide perovskite, thereby underscoring the immense potential of this material for future memory applications. By incorporating polyvinylpyrrolidone (PVP) into the device structure, which consists of MAPbI${}_{3-}$${}_x$Cl${}_x$ sandwiched between top (Au) and bottom (ITO) electrodes, we achieved a remarkable morphological transition from elongated, needle-like structures to denser, more compact forms. This morphological evolution was pivotal in significantly lowering operational voltages, with “SET” and “RESET” voltages dramatically reduced from 7 V to 0.7 V and −2.2 V to −0.2 V, respectively. The incorporation of PVP proved to be a key factor in this achievement, as it enhanced charge transport within the device, minimized energy barriers, and markedly improved the dielectric properties of the perovskite material. These enhancements contributed directly to the observed reduction in switching voltages, marking a substantial leap forward in the quest for more efficient, stable, and low-power RRAM devices. Our research not only advances the field of memory technology but also emphasizes the critical aspects of reduced power consumption and the potential for enhanced device stability. This significant decrease in energy requirements, coupled with the prospect of increased device longevity, underscores the transformative impact of our findings, paving the way for the development of sustainable and reliable memory technologies that are well-suited to meet the demands of future electronic devices and systems.

The administration of photosensitizers and their biocompatibility is crucial to the success of photodynamic therapy treatment. Amongst the various strategies developed to administer photosensitizers of low water-solubility, the use of polyvinylpyrrolidone (PVP), an FDA-approved food additive, is emerging as extremely promising. Its effect on photodynamic outcome was compared to more classical formulation in DMSO and direct solubilization in water. The tetrakis (2-(2-(2-methoxyethoxy) ethoxy)ethoxy)-Zn(II) phthalocyanine chosen as the model photosensitizer for this study proved to be a powerful photosensitizer. Even if slightly less efficient than DMSO formulation, PVP formulation proved to work very well, with submicromolar IC₅₀ and IC₉₀ values against MDA-MB-231 human cancer cells.