In this study, we designed a novel hydrogel composite membrane based on the combination of polyvinyl alcohol (PVA), agar, and maltodextrin through a facile solution‐casting router. From Fourier‐transform infrared spectroscopy, contact angle, scanning electron microscopy, and swelling analyses, the formation of hydrogen bonds between surface functional groups of PVA, agar, and maltodextrin was confirmed. As a result, the PVA/agar/maltodextrin membranes exhibited a more hydrophobic nature compared with pure PVA. The thermal stability and integrity of such obtained composite membranes were also elucidated by the evaluation of thermogravimetric analysis and mechanical behavior. Besides, the composite membrane exhibited high selective adsorption for cationic dyes, namely 20.2 mg g−1 for methylene blue and 19.17 mg g−1 for crystal violet at initial dye concentration of 100 mg/L, an adsorbent dosage of 0.1 g, contact time of 180 min, and solution pH 7, while anionic dyes such as congo red and methyl orange are approximately zero. The adsorption kinetics and isotherm of the as‐prepared composite membranes were well fitted to the pseudo‐second‐order and Temkin model. The effect of factors, including contact time, solution pH, PVA content, and initial dye concentration on the adsorption capacity of the as‐prepared composite membrane was also investigated in detail. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 137, 48904.

Green thin films for food packaging are essential and growing in recent years to reduce the dependence on petroleum‐derived plastics. In this study, the glycerol‐plasticized chitosan film incorporated with 1–3% of crude Piper betel Linn. leaf (PBLL) extract was prepared via facile casting process and was characterized by scanning electron microscope, attenuated total reflection‐Fourier transform infrared, thermogravimetric analysis, X‐ray diffraction, UV–Vis, contact angle, water content, antimicrobial, and antioxidant activities. The film improved the protective properties of the sole chitosan and enhanced the UV‐blocking ability of glycerol‐plasticized chitosan film in the regions of Ultraviolet B (280–320 nm) and Ultraviolet A (320–390 nm), resulting in suitable film for food packaging applications. Furthermore, the presence of PBLL extract predominantly containing phenolic compounds in blend film induced very strong antimicrobial activities against Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella typhimurium, and Escherichia coli. The modified chitosan films increased the hydrophilic property resulting in high potential in degradability and can also protect the king orange by coating with the shelf life‐prolonging up to 18 days at 20°C with acceptable appearance and texture. Our results can be developed to produce industrial green thin films to protect fruits during transportation and preservation.

A simple chemical reduction method is used to prepare colloidal bimetallic Cu-Ag core-shell (Cu@Ag) nanoparticles. Polyvinyl pyrrolidone (PVP) was used as capping agent, and ascorbic acid (C 6 H 8 O 6 ) and sodium borohydride (NaBH 4 ) were used as reducing agents. The obtained Cu@Ag nanoparticles were characterized by powder x-ray diffraction (XRD), transmission electron microscopy (TEM) and UV-vis spectrophotometry. The influence of [Ag]/[Cu] molar ratios on the formation of Ag coatings on the Cu particles was investigated. From the TEM results we found that the ratio [Ag + ]/[Cu 2+ ] = 0.2 is the best for the stability of Cu@Ag nanoparticles with an average size of 22 nm. It is also found out that adding ammonium hydroxide (NH 4 OH) makes the obtained Cu@Ag nanoparticles more stable over time when pure deionized water is used as solvent.

Nanostructured cathode materials based on Mn-doped olivine LiMnxFe1−xPO4 (x = 0, 0.1, 0.2, and 0.3) were successfully synthesized via a hydrothermal route. The field-emission scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) analyzed results indicated that the synthesized LiMnxFe1−xPO4 (x = 0, 0.1, 0.2, and 0.3) samples possessed a sphere-like nanostructure and a relatively homogeneous size distribution in the range of 100–200 nm. Electrochemical experiments and analysis showed that the Mn doping increased the redox potential and boosted the capacity. While the undoped olivine (LiFePO4) had a capacity of 169 mAh g−1 with a slight reduction (10%) in the initial capacity after 50 cycles (150 mAh g−1), the Mn-doped olivine samples (LiMnxFe1−xPO4) demonstrated reliable cycling tests with negligible capacity loss, reaching 151, 147, and 157 mAh g−1 for x = 0.1, 0.2, and 0.3, respectively. The results from electrochemical impedance spectroscopy (EIS) accompanied by the galvanostatic intermittent titration technique (GITT) have resulted that the Mn substitution for Fe promoted the charge transfer process and hence the rapid Li transport. These findings indicate that the LiMnxFe1−xPO4 nanostructures are promising cathode materials for lithium ion battery applications.

Solutions and redispersible powders of nanocrystalline, europium-doped YVO4, are prepared via a wet chemical method using the ultrasonic processor (sonochemical) and microwave and thermal stirring. From X-ray diffraction (XRD) results, YVO4:Eu3+ nanoparticles synthesized using sonochemical method have better crystallinity than those prepared using thermal stirring and microwave methods exhibiting the tetragonal structure known for bulk material. From field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) results, it is found that the size of nanoparticles is around 25 nm and increasing after annealing at 900°C. From UV-Vis result, there is a peak at 270 nm corresponding to the absorption of VO43− groups. The photoluminescence (PL) results clearly show the strongest red emission peak at the wavelength around 618 nm. The highest luminescent intensity is obtained for the sample prepared by the sonochemical method at pH = 12 and annealing temperature at 900°C for 4 h. The average lifetimes of the Eu3+ ions in the samples annealed at 300, 600, and 900°C for 1 h at 618 nm emission under 275 nm excitation are 0.36, 0.62, and 0.64 ms, whereas sample annealed at 900°C for 4 h has lifetime of 0.70 ms. The security ink, containing synthesized YVO4:Eu3+ nanoparticles, is dispersed in glycerol and other necessary solvents. The experimental security labels are printed by inkjet using the electrohydrodynamic printing technique. The resulting lines represented to the security labels are analyzed by the 3D microscope equipment and UV 20 W mercury lamp with a wavelength of ∼254 nm. The seamless line of the printed security label has the value of the width at ∼230 μm, thickness at ∼0.68 μm, and distance between two adjacent lines at 800 μm. This result is compatible for producing security labels in small size (millimeter) in order to increase security property.