Zinc Oxide Content Research Articles

Improved Electrical Signal of Non-Poled 3D Printed Zinc Oxide-Polyvinylidene Fluoride Nanocomposites.

Polyvinylidene fluoride (PVDF) presents highly useful piezo and pyro electric properties but they are predicated upon the processing methods and the ensuing volume fraction of the β-phase. Production of PVDF with higher β-phase content for additive manufacturing (AM) is particularly desirable because it can enable the creation of custom parts with enhanced properties. Necessary steps from compounding to the testing of a 3D printed piezo sensitive sensor are presented in this paper. AM process variables and the influence of zinc oxide (ZnO) nanofiller on crystallinity, viscosity, and electromechanical properties of PVDF, have been explored. Fourier-transform infrared spectroscopy (FTIR) measurements confirm that a high cooling rate (HCR) of 30 °C min−1 promotes the conversion of the α-into the β-phase, reaching a maximum of 80% conversion with 7.5–12.5% ZnO content. These processing conditions increase the elastic modulus up to 40%, while maintaining the ultimate strength, ≈46 MPa. Furthermore, HCR 10% ZnO-PVDF produces four times higher volts per Newton when compared to low cooling rate, 5 °C min−1, pristine PVDF. A piezoelectric biomedical sensor application has been presented using HCR and ZnO nanofiller. This technique also reduces the need for post-poling which can reduce manufacturing time and cost.

Solution blowing spinning of polylactate/polyvinyl alcohol/ZnO nanocomposite toward green and sustainable preparation of wound dressing nanofibrous films.

The outstanding biodegradability, biocompatibility, affordability, and renewability of polylactic acid have made it a prominent biomaterial. Herein, an innovative, easy, and eco-friendly technique is used to prepare sodium polylactate (SP)-based nanofibers. Solution blowing spinning (SBS) was used to create fibrous mats of SP and polyvinyl alcohol (PVA). SBS's SP nanfibers were crosslinked using an aqueous solution of calcium chloride to produce moisture-resistant calcium polylactate nanofibrous spun mats. Both of UV-visible absorption spectra and transmission electron microscopy were utilized to study the produced zinc oxide (ZnO) nanoparticles (NPs) to indicate a diameter of around 15-23 nm with a high intensity absorption intensity at 370 nm. New polylactate copolymer was synthesized and characterized by infrared and NMR spectroscopic techniques. In order to prepare SP/PVA/ZnO nanocomposite nanofibers, various ZnO ratios were used. The morphologies of the composite nanofibers were investigated by infrared spectroscopy (FTIR), energy-dispersive X-ray analyzer, and scanning electron microscopy. The cytotoxicity tests of the prepared mat were studied by conducting experiments with L-929 cells at various time intervals. The prepared composite SP/PVA/ZnO nanofibers were subjected to cytotoxicity tests to determine their cytocompatibility. Results showed that those with ZnO concentrations between 0.5% and 2% were found to be less harmful than those with higher concentrations. A variety of bacterial species, including Bacillus pumilus and Staphylococcus aureus, as well as Klebseilla pneumoniae and Escherichia coli, were used to test the antibacterial properties of SP/PVA/ZnO spun mats. The ZnO NPs integrated in the SP/PVA fibrous mats were responsible for their antibacterial properties. After finding the appropriate concentration of ZnO that is least harmful while yet giving a satisfactory antibacterial activity, this biomaterial might be perfect for wound dressing applications. HIGHLIGHTS: New eco-friendly biodegradable sodium polylactate (SP) copolymer was synthesized. Zinc oxide nanoparticles (ZnO NPs) with a diameter of 15-23 nm were prepared. High antibacterial SP/PVA/ZnO fibers were prepared by solution blowing spinning. SP/PVA/ZnO nanofibers (180-220 nm) with various ratios of ZnO were presented. Cytotoxicity results showed that the cell viability decreases with increasing ZnO.

Toxic and bioaccumulative effects of zinc nanoparticle exposure to goldfish, Carassius auratus (Linnaeus, 1758)

The widespread use of produced metal oxide nanoparticles (NPs) has increased major concerns about their impact on human as well as aquatic animal health. The present study shows that exposure to different concentrations of zinc oxide (ZnO) NPs led to high accumulations of Zn ions in the metabolic organs of fish (liver and gills), resulting in severe oxidative stress in Carassius auratus. The goldfish (C. auratus) was chosen as an aquatic species for the evaluation of the potential toxicity of aqueous ZnO-NPs (Treatments of hemoglobin and neutrophils (0, 0.5, 1, and 1.5 mg L− 1) following 14 days of exposure. A range of histological and hematological factors were examined. Exposure to the NPs produced significant reduction of red blood cell and white blood cell counts, hematocrit) were found to produce no significant differences in lymphocyte, monocyte, and eosinophil counts; as well as the mean corpuscular hemoglobin concentrations index (P > 0.05). Moreover, the results revealed significant alterations in serum biochemical parameters, hepatic enzyme levels, and immune and antioxidant responses; except for total protein and superoxide dismutase (SOD) of C. auratus exposed to ZnO-NPs, particularly at the 1 and 1.5 mg L− 1 concentrations. Fish exposed to 1 and 1.5 mg L−1 ZnO-NPs displayed a significant reduction in alternative complement pathway activity, lysozyme, and total protein contents of mucus compared to those in the control group. The results showed that hepatic SOD and catalase, and gill catalase activity were significantly decreased, and their malondialdehyde levels increased at 1 and 1.5 mg L−1 ZnO-NPs compared to the control group (P < 0.05). Significant accumulations of ZnO-NPs were observed in the liver, kidney, and gill tissues of fish leading to severe histopathological alterations in these organs. These results suggest that water-borne ZnO-NPs can easily accumulate in metabolic organs and lead to oxidative stress and destructive effects on the physiological features of C. auratus.

Long-term Photo-degradation of Nanofibrous Composites Based on Poly(3-hydroxybutyrate) Electrospun Fibers Loaded with Zinc Oxide Nanoparticles

Composite mats based on submicron biopolyester fibers, such as poly(3-hydroxyalkanoate)s, and zinc oxide (ZnO) nanoparticles have been exploited in medicine and environmental areas, as antibacterial wound dressings or filters. Generally, the resulting mats have to be subjected to UV irradiation in order to promote the formation of reactive oxygen species, thus activating the antimicrobial or photocatalytic effect of ZnO. Therefore, investigation related to the influence of ZnO on poly(3-hydroxyalkanoate)s photo-degradation is required. In this context, the present paper addresses the long-term photo-degradation of nanofibrous poly(3-hydroxybutyrate) (PHB)/ZnO composites derived from two complementary electro-hydrodynamic techniques, namely electrospinning or electrospinning/electrospraying tandem processes. A thorough investigation of the as-obtained PHB/ZnO fibrous composites implying the utilization of ATR-FTIR, SEC, and SEM analysis pre- and post-aging under UV irradiation (313 nm) for a period of time of 500 h to study the effect of electro-hydrodynamic technique utilized and the ZnO content on the UV shielding properties of PHB mats.

Hydrothermal synthesis, characterization and antimicrobial activity of Ag-modified ZnO nanoplates against pathogen

Antibiotic resistance is concerned with public health and a serious threat in modern world. Pathogenic strains are rapidly developing resistance against antibiotics and limiting the treatment options. Nanostructured zinc oxide (ZnO) shows significant results when doped with silver (Ag), therefore used as an antibacterial agent. In this work, we synthesized pure and varying concentration of Ag-doped ZnO nanoplates through a one-step hydrothermal route. The structural, morphological, and optical properties of prepared nanostructures were comparatively studied. Furthermore, we have performed the ager-well assay, minimum inhibitory concentration study, and minimum bactericidal concentration study of synthesized nanoplates against five different bacterial strains including A. baumannii, P. aeruginosa, E. coli, K. pneumoniae, and S. aureus. The antimicrobial screening shows that Ag-doped ZnO nanoplates are more effective against all pathogenic strains as compared to pure ZnO, and therefore can be used in biomedical science.

ZnO induced self-crystallization of CsPb(Br/I)3 nanocrystal glasses with improved stability for backlight display application

• With further the integration of green-emitting CsPbBr3@glasses powder, a flexible film with white light-emitting were obtained by sandwiching and gluing mixed glasses powders between two layers of hydrophobic and transparent PET films. • A high-resolution backlight image is acquired by putting PET composite film into the backlight device. • The content of lead can hardly dissolve from ZnO induced self-crystallized CsPb(Br/I)3@glass, indicating its excellent environmental friendliness. • The maximum PLQY of the obtaining CsPb(Br/I)3@glass composite is of 30% with the content of ZnO was 13 mol%. • The FWHM (34–44 nm) can be well modified by tailoring the content of ZnO. • ZnO can not only be used as a flux to reduce the sintering temperature of glass, but also as a network modifier to make the glass structure more stable. • wLEDs are constructed and applied in backlit display, achieving a color gamut covering up 126% of NTSC and 93.4% of Rec. 2020. • The outstanding stability towards water, cyclic thermal and 455 nm LED irradiation benefit from the protection of the robust glass matrix. In the current situation of energy shortages, saving energy and reducing consumption are undoubtedly valid methods to relieve the pressure on resources. CsPb X 3 ( X = Cl, Br, and I) perovskites as star inorganic materials have drawn growing attention owing to their unique properties, making them suitable for applications such as light-emitting diodes (LEDs), solar cells, photodetectors, or lasers. This work presents zinc oxide (ZnO) induced self-crystallized CsPb(Br/I) 3 perovskite with a 26% photoluminescence quantum yield (PLQY) prepared by the traditional melt-quenching method. Furthermore, the full width at half maximum (FWHM) (34–44 nm) can be regulated by the ZnO content. In addition, as a downconverter, CsPb(Br/I) 3 perovskite nanocrystals (NCs) realize a bright red backlight that covers ≈ 94% Rec. 2020 standards in the CIE 1931 color space and 126% of National Television System Committee (NTSC). This finding undoubtedly confirms an effective path for fabricating perovskite materials in a green, low-cost, and time-saving way, enriching the knowledge of glass crystallization mechanisms and promoting their applications in wide color gamut backlights.

Thermodynamic modeling of metal reduction in copper-smelting slags and experimental verification of its results

Over 110 million tons of slag were accumulated in the dumps of the Russian copper-smelting enterprises, and their number is increasing. Environmental taxes and dumps maintenance costs are burdensome, which makes it necessary to make the most complete disposal of these production wastes. At the same time, these slags contain valuable elements, in particular, iron, copper, zinc, selenium, arsenic and some others, the extraction of which can make recycling profitable. The paper presents the results of a thermodynamic calculation of the behavior of copper-smelting slag elements in the mixture with carbon during heating. Modeling was performed using the TERRA software package. The influence of the process temperature in the range of 600 – 1750 °C on reduction of iron, zinc and silicon was analyzed at the amount of carbon in the system corresponding to the stoichiometry of iron reduction reactions and exceeding the stoichiometric one. It was established that when heated above 650 °C, metallic iron appears in the system, and its full reduction is completed at 1250 °C. The appearance of metallic zinc is observed in two temperature ranges: in the first, appearance of zinc is observed with a simultaneous decrease in concentration of zinc oxide; in the second, an increase in concentration of metallic zinc with a simultaneous decrease in concentration of zinc sulfide. At temperatures above 1650 °C, silicon appears in the system. Under laboratory conditions, the processes of solid-phase reduction of iron with the capture of zinc oxide and separation of the reduction products were tested. It was established that as a result of pyrometallurgical separation by melting reduction products, iron-carbon alloys (steel and cast iron) and alloys with high silicon content can be obtained. The results of the work can be used in development of theoretical and technological foundations for the processing of copper smelting slags, which are not processed by existing technologies.

Cerium Oxide Enhances the Toxicity of Zinc Oxide Nanoparticles in Human Lung Epithelial Cell Cultures.

Recently, many approaches have been developed to improve the performance of nanomaterials. Combining more than one nanomaterial is one such approach that achieves superior results. However, during the fabrication of nanomaterials or formulation of end products, materials can be released into the ambient air and be inhaled by workers. The adverse health outcomes of inhaling such compounds are unknown. In this study, we examined such effects in combining two of the most utilized nanomaterials in several industrial sectors: zinc oxide (ZnO) and cerium oxide (CeO2). These materials can be found together in sunscreens, polyvinyl alcohol (PVA) films, and construction products. The aim of this study was to assess the adverse biological outcomes of CeO2–ZnO nano-mixtures in human lung epithelial cells. A549 human lung epithelial cells were treated with increasing concentrations of ZnO or CeO2 NPs alone, or as a mixture of both, under submerged conditions for 24 h. After treatment, cell viability, reactive oxygen species (ROS) formation, cell membrane integrity, and cytokine production were examined. ZnO NPs showed a dose-dependent trend for all endpoints. CeO2 NPs did not exhibit any toxic effect in any individual concentrations. When higher doses of ZnO were combined with increasing doses of CeO2, loss of cell viability and an elevation in cell membrane leakage were observed. Interleukin 8 (IL-8) and ROS generation were higher when ZnO NPs were combined with CeO2 NPs, compared to cells that were treated with ZnO alone. The release of monocyte chemoattractant protein-1 (MCP-1) was reduced in the cells that were treated with higher doses of ZnO and CeO2. Thus, the presence of CeO2 enhanced the toxicity of ZnO in A549 cells at non-toxic levels of CeO2. This suggests an additive toxicity of these two nanomaterials.

Electroexplosive synthesis of composite ZnO/ZnFe2O4/Zn nanoparticles with photocatalytic and antibacterial activity

Composite ZnO/ZnFe2O4/Zn nanoparticles with zinc oxide content 25–75 at % were synthesized for the first time by electrical explosion of two twisted wires in one stage in an oxygen-containing atmosphere. The morphology, phase composition, textural characteristics, optical properties and antibacterial activity against antibiotic-resistant bacteria MRSA have been investigated. The sample with the highest ZnO content (70 at.% ZnO) demonstrates significant degradation of the MB. Degradation reached 72 % within 120 min of the experiment in the visible light irradiation that was higher than that of ZnO nanoparticles produced by electric explosion of zinc wire in oxygen. Nanoparticles had enhanced antibacterial activity against MRSA which is based on reactive oxygen species generation. The ZnO/ZnFe2O4/Zn nanoparticles have prospects for widespread use in the fields of water purification and biomedicine as promising antimicrobial agents.

Implementation of Antibacterial Nanoparticles in Additive Manufacturing to Increase Part Strength and Stiffness

The introduction of novel composites suited for additive manufacturing machines offers a solution for the current slow adoption of the technology. Many composites offer secondary functions and mechanical improvements to suit unique applications better. This article presents the creation of a set of novel nanocomposites consisting of zinc oxide (ZnO) and a photocurable resin using a masked stereolithography additive machine. These nanocomposites are produced in 1%, 2.5%, 5%, and 7.5% concentrations and are characterized based on their mechanical and surface properties. Using ZnO allows for the creation of mechanically stronger parts with reduced wettability while offering antibacterial properties throughout the entire part. Best results were observed at a 5% concentration of ZnO with a nearly 25% strength increase and 45% decrease in wettability. Additionally, SEM analysis demonstrated proper dispersion with minimal agglomerations present. In the sporicidal effect analysis, the ZnO (with 7.5% concentration) reduced 31.5% of Clostridioides difficile spores. These results demonstrate the capability of producing antibacterial nanocomposites using low-cost additive manufacturing to enhance public health options.

Microwave-assisted synthesis of poly (acrylamide-co-2-hydroxyethyl methacrylate)/chitosan semi-IPN ZnO nanocomposite membranes for food packaging applications

Microwave irradiation is used in this study to synthesize poly (acrylamide-co-2-hydroxyethyl methacrylate)/chitosan (P(AM-co-HEMA)/chitosan) semi-IPN hydrogels, which are synthesized using one-pot polymerization techniques with ammonium persulfate (APS) as an initiator. The first step was to synthesize a (P(AM-co-HEMA) network in a chitosan aqueous solution, which formed a semi-IPN structure. Nanocomposite membranes of P(AM-co-HEMA)/chitosan membranes with varying Zinc oxide concentrations i.e. 2.5, 5, and 10 wt. % gravimetrically were tested for gas permeability measurements of pure oxygen gas at feed pressures ranging from 1 to 20 kg/cm2. The permeability of the membranes to oxygen ranged from 0.0963 to 0.2634 Barrer for the pristine Poly (Acrylamide-co-2-Hydroxyethyl Methacrylate)/Chitosan Semi-IPN membrane, and 5 and 10 wt. % ZnO loaded blend membranes showed good resistance and zero permeability at feed pressures of 1–5 kg/cm2 and 0.0341 to 0.0364 Barrer for 10 wt. % ZnO loaded blend membranes by increasing the feed pressures at the feed chamber. The nanocomposite membranes were tested for antimicrobial properties and found to be a more effective antimicrobial material. The results of the soil burial tests show that the prepared membranes are biodegradable. Mechanical strength is exceptional under normal conditions.

Adhesive Bond Integrity of Experimental Zinc Oxide Nanoparticles Incorporated Dentin Adhesive: An SEM, EDX, μTBS, and Rheometric Analysis.

Objective Our study is aimed at preparing an experimental adhesive (EA) and assessing the influence of adding 5-10 wt.% concentrations of zinc oxide (ZnO) nanoparticles on the adhesive's mechanical properties. Methods Field emission scanning electron microscopy (FESEM) and energy dispersive X-ray (EDX) spectroscopy were employed to investigate the morphology and elemental distribution of the filler nanoparticles. To examine the adhesive properties, microtensile bond strength (μTBS) testing, an investigation of the rheological properties, degree of conversion (DC), and analysis of the interface between the adhesive and dentin were carried out. Results The SEM micrographs of ZnO nanoparticles demonstrated spherical agglomerates. The EDX plotting confirmed the incidence of Zn and oxygen (O) in the ZnO nanoparticles. The highest μTBS was observed for nonthermocycled (NTC) 5 wt.% ZnO group (32.11 ± 3.60 MPa), followed by the NTC-10 wt.% ZnO group (30.04 ± 3.24 MPa). Most of the failures observed were adhesive in nature. A gradual reduction in the viscosity was observed at higher angular frequencies, and the addition of 5 and 10 wt.% ZnO to the composition of the EA lowered its viscosity. The 5 wt.% ZnO group demonstrated suitable dentin interaction by showing the formation of resin tags, while for the 10 wt.% ZnO group, compromised resin tag formation was detected. DC was significantly higher in the 0% ZnO (EA) group. Conclusion The reinforcement of the EA with 5 and 10 wt.% concentrations of ZnO nanoparticles produced an improvement in the adhesive's μTBS. However, a reduced viscosity was observed for both nanoparticle-reinforced adhesives, and a negotiated dentin interaction was seen for 10 wt.% ZnO adhesive group. Further research exploring the influence of more filler concentrations on diverse adhesive properties is recommended.

Zinc oxide reinforced poly(para-aminophenol) nanocomposites: Structural, thermal stability, conductivity and ammonia gas sensing applications

Conducting polymer nanocomposites based on poly(para-aminophenol) (PpAP) with various concentrations of zinc oxide (ZnO) nanoparticles were synthesized by in-situ polymerization and their structural, morphological, thermal and electrical properties were evaluated. X-ray diffraction and Fourier transform infrared analysis were used to ascertain the interfacial interactions between ZnO and PpAP. The scanning and transmission electron microscopic images demonstrate the variation in morphology of composites with a homogenous growth of spherically shaped nanoparticles in the polymer matrix. Thermogravimetric studies supported the increased thermal stability of the composites compared to the parent polymer, and thermal activation energy from the Coats-Redfern method further corroborated this finding. The dielectric properties and AC conductivity increase with the addition of nanoparticles up to 7 wt.% and beyond that, these properties decrease. The applicability of various theoretical models for predicting the dielectric constant for PpAP/ZnO nanocomposites was evaluated. The synthesized nanocomposites were used for detecting ammonia gas at room temperature, and the composite with 7 wt.% sample had the best gas sensing performance. Finally, the gas-sensing mechanism has been systematically studied to illustrate the improved sensing properties combining p-n junction with interfacial interactions. The excellent properties of these nanocomposites provide a new horizon for designing gas-sensors and nano-electronic devices.

The effect of ZnO (zinc oxide) and glycerol concentrations on the mechanical properties of bioplastics made from Canna tuber (Canna edulis) starch

The problem of plastic waste in Indonesia is increasingly worrying due to its long degradation duration. Bioplastics made from starch are easily degradable in nature and have a lower contribution to environmental pollution. This study aimed to determine the effect of ZnO and glycerol additions on the thickness, tensile strength, elongation, Young’s Modulus, water absorption, and biodegradation of bioplastics. The results indicate that adding ZnO and glycerol has significant effects on thickness, tensile strength, elongation, Young’s Modulus, water absorption, and biodegradation. A high concentration of ZnO and glycerol was parallel to an increase in the thickness of bioplastic. A high ZnO concentration and low glycerol concentration increases the tensile strength and Young’s Modulus, but decreases the water absorption. Glycerol at high concentration and ZnO at low concentration increases the elongation. The addition of ZnO in a small amount positively affects the biodegradation of bioplastics.

Investigating the Antibacterial Properties of ZnO-NPs

The size range of several hundred nanometers to several of micrometers contains a lot of microorganisms. The aim of the current report was to study the antibacterial properties of ZnO-NPs through a theoretical review of the most important findings in previous studies. The study found the most important antibacterial properties of ZnO-NPs, including: Strong antibacterial results can be achieved by enhancing variables such as UV light, zinc oxide particle size, concentration, shape, and surface modification, which affect many different toxicological processes. One of the main properties of ZnO-NPs is the production of intracellular ROS formation, as well as the mechanical damage of the cell wall due to the release of Zn2+ ion and its attachment to the cell membrane.

Fabrication, characterization and antibacterial properties of ZnO nanoparticles decorated electrospun polyacrylonitrile nanofibers membranes

Zinc oxide (ZnO) was widely used in antibacterial applications due to the excellent physicochemical properties and unique bioactivities. However, powdery ZnO could give rise to further problems, such as the agglomeration, easy deactivation, the difficult recovery during the used process, and so on. In this study, polyacrylonitrile nanofiber membranes (PAN NFMs) had been electrospun and reinforced with organic Hectorite (OHec). Further, prepared NFMs decorated with ZnO via surface modification technique, denoted as ZnO-g-PAN NFMs. The characterizations of pure PAN and ZnO-g-PAN NFMs were investigated by means of FESEM, FTIR, XRD and TG, furthermore, antibacterial properties were also analyzed. The results indicated that the surface morphology of ZnO-g-PAN NFMs became uneven, rough and irregular compared with raw PAN. The incorporation of ZnO and OHec in the fibers mainly enhanced the mechanical properties of NFMs. The hydrophilicity and surface roughness of NFMs increased with increasing of the ZnO concentration. In particular, ZnO-g-PAN NFMs exhibited excellent antibacterial activities, which was approved by the fact that they revealed the antibacterial rates of 97.7 % against Escherichia coli (E. coli) and 98.2 % against Staphylococcus aureus (S. aureus). Further, NFMs showed good cytocompatibility with L929 cells. These results demonstrated that ZnO-g-PAN NFMs would have a great potential for antibacterial applications.

Emphasized temperature dependent electrical properties study of fabricated ZnO/PVA/PANI nanocomposite films

Polyvinyl alcohol-Polyaniline composite films with different amounts of zinc oxide (ZnO) (0.2%, 0.4%, 0.6% and 1%)were prepared by in situ polymerization followed by film casting and drying. The samples, ZnO and PPZ films, were characterized by various techniques. The presence of ZnO in PPZ films was confirmed by the X-Ray Diffractometer (XRD). The surface morphology of the ZnO and PPZ films were examined by the Field-Emission Scanning Electron Microscopy(FESEM). The formation of absorption bonds corresponding to the PPZ films were illustrated by the Fourier Transform Infrared Spectroscope (FTIR)analysis. The films were found to be stable up to 150 °C, which was confirmed from the Differential Scanning Calorimetry (DSC) and Thermo-Gravimetric Analyzer (TGA) technique. The absorption peaks of PPZ, around visible and UV region, was studied by the UV–Vis spectra. The electrical conductivity plots obtained from the impedance analyzer, between frequency ranges of 10 Hz to 100 kHz, show that the increase in concentration and temperature of the samples resulted in the higher conductivity of the PPZ films. For 1% ZnO concentration at 150 °C, the AC conductivity of PPZ1 was found to be 20.06 S/m. Such conductivity behavior samples render the applicability of the PPZ films.

Investigation of self-cleaning attributes of denim fabric modified with naturally synthesized ZnO nanoparticles

PurposeThe textile sector is moving towards new technologies, where the application of nanotechnology is offering fabrics with multifunctional properties making fabric odourless, hydrophobic, durable and self-cleaning. This aim of this research is to investigate self-cleaning ability of denim fabric with the application of zinc oxide nanoparticles (ZnO NPs) synthesized naturally. The primary focus of this investigation is achieving sustainability mark through green synthesis of ZnO NPs.Design/methodology/approachIn this analysis, ZnO NPs being one of the metal oxides exhibiting self-cleaning, UV-protective and anti-microbial properties were synthesized naturally using Azadirachta Indica leaves. The prepared NPs were characterized by using X-ray diffraction and scanning electron microscopy analyses confirming their size and crystalline structure. Different formulations were investigated with varying concentration of zinc oxide and auxiliaries onto the denim fabric using pad-dry-cure application technique.FindingsXRD analysis confirmed the successful green synthesis of ZnO NPs. SEM analysis revealed the homogeneous and hexagonal wurtzite NPs deposition on the denim fabric. It was ascertained that with 5% ZnO NPs and 7% Binder concentrations, the formulation resulted in a smooth and even layer on the denim fabric maintaining the appearance and feel at the same time offers appreciable grading (Grade 4) against the stringent stains of Ketchup, Coffee, Grape and Orange Juice with insignificant change in tensile strength.Originality/valueIn this study, self-cleaning attributes of denim fabric with zinc oxide nano formulations of different composition was studied to achieve promising functional properties in a single step not studied earlier.

Properties and biological activity of chitosan-coix seed starch films incorporated with nano zinc oxide and Artemisia annua essential oil for pork preservation

Edible films based on chitosan, coix seed starch (CSS), nano zinc oxide (ZnO) and Artemisia annua essential oil (AO) were obtained through solvent casting method. Physico-chemical, biological properties and structures of the edible film were analyzed and the preservation effect of it on the quality of cold-stored pork was also investigated. Fourier-transform infrared spectroscopy (FTIR) indicated that some possible intermolecular interactions could exist between film matrix and ZnO or AO. Scanning electron microscope (SEM) and thermogravimetry (TG) showed that ZnO and AO had good compatibility with the film biopolymers, no any phase separation. Results suggested that appropriate content of ZnO could enhance the film's compactness. Tensile strength (TS), barrier properties and antibacterial activities of the film was significantly enhanced with 5% ZnO was added. Incorporation of AO into the edible film decreased the TS, but increased the flexibility, barrier properties, antibacterial and antioxidant activities. When content of ZnO and AO were 5% and 8%, the physico-chemical, biological properties of the edible film could reach optimum. For pork preservation, pH, thiobarbituric acid reactive substances (TBARS), total viable count (TVC), and total volatile basic nitrogen (TVB-N) values of the pork which treated with 5% ZnO-8% AO film were significantly lowest (p ≤ 0.05) than other groups. Therefore, this edible film system has potential as food packaging materials.

High Gas Sensitivity to Nitrogen Dioxide of Nanocomposite ZnO-SnO2 Films Activated by a Surface Electric Field.

Gas sensors based on the multi-sensor platform MSP 632, with thin nanocomposite films based on tin dioxide with a low content of zinc oxide (0.5–5 mol.%), were synthesized using a solid-phase low-temperature pyrolysis technique. The resulting gas-sensitive ZnO-SnO2 films were comprehensively studied by atomic force microscopy, Kelvin probe force microscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, scanning transmission electron microscopy, energy dispersive X-ray spectrometry, and X-ray photoelectron spectroscopy. The obtained films are up to 200 nm thick and consist of ZnO-SnO2 nanocomposites, with ZnO and SnO2 crystallite sizes of 4–30 nm. Measurements of ZnO-SnO2 films containing 0.5 mol.% ZnO showed the existence of large values of surface potential, up to 1800 mV, leading to the formation of a strong surface electric field with a strength of up to 2 × 107 V/cm. The presence of a strong surface electric field leads to the best gas-sensitive properties: the sensor’s responsivity is between two and nine times higher than that of sensors based on ZnO-SnO2 films of other compositions. A study of characteristics sensitive to NO2 (0.1–50 ppm) showed that gas sensors based on the ZnO-SnO2 film demonstrated a high sensitivity to NO2 with a concentration of 0.1 ppm at an operating temperature of 200 °C.