The impact of film thickness on the properties of ZnO/PVA nanocomposite film

New polyvinyl alcohol (PVA) nanocomposites containing zinc oxide (ZnO) nanoparticles and a hydrogel were prepared by the solution casting method. ZnO nanoparticles grafted co‐polymer (Zn‐g‐CP) was synthesized through the reaction of ZnO nanoparticles with vinyltriethoxysilane and then the radical co‐polymerization with 2‐acrylamido‐2‐methylpropane sulfonic acid (AMPS). The amide functionalized hydrogel was prepared via an in situ polymerization of acrylamide and N,N′‐methylene bisacrylamide (MBA) as a crosslinker in a solution of PVA. The corresponding results indicated that the simultaneous presence of both Zn‐g‐CP and hydrogel could significantly increase flammability, thermal stability, and the tensile strength of PVA. The results of the X‐ray diffraction (XRD) and field‐emission scanning electron microscopy (FE‐SEM) indicated a uniform dispersion of ZnO nanoparticles and an enhanced compatibility with the PVA matrix. Thermogravimetric analysis (TGA) in both N2 and air atmospheres, indicated that the temperature at 50% mass loss and the char residue values of PVA nanocomposite containing 6 wt% of Zn‐g‐CP in the presence of hydrogel (PZH12 sample) were enhanced, which was evident by the increased thermal decomposition temperature. The peak of heat release rate (pHRR) value of the PZH12 sample was obtained 56.9% lower than that of the neat PVA demonstrating a significant improvement in flammability behavior. Also, the flame‐retardant performance of PZH12 improved, as compared to the pure PVA, with UL‐94 V1 rating and LOI of 27.2%. The tensile strength (Ts) and elongation at break (EB) values for the mentioned sample enhanced by 62.5% and 7.2% compared to those of the neat PVA, respectively.Highlights Preparation of vinyl functionalized ZnO nanoparticles (VZnO). ZnO grafted co‐polymer (Zn‐g‐CP) from a radical polymerization on the VZnO surface. Preparation of an amide‐sulfonated hydrogel in the PVA solution. The effect investigation of hydrogel and Zn‐g‐CP on the PVA properties. The results exhibited the enhanced flame retardancy and mechanical properties of PVA.

ZnO nanoparticles infused PVA-hyaluronic acid based hydrogel: An alternative solution for skin wound.

Synthesis, characterization and conducting properties of novel poly (vinyl cinnamate)/zinc oxide nanocomposites via in situ polymerization

With the rapid expansion of nanotechnology, studies focusing on the toxicity of nanomaterials to living organisms are increasing. Nanoparticles (NPs) are widely used in pest control because of their various toxicological effects on insects. The changes in the amounts of malondialdehyde (MDA), the activities of NADPH oxidases (NOX), superoxide dismutase (SOD) and catalase (CAT), and the amount of glutathione (GSH) of Malacosoma neustria L. (Lepidoptera: Lasiocampidae) larvae, a polyphagous species, exposed to different concentrations of copper oxide (CuO) and zinc oxide (ZnO) NPs were compared in this study. M. neustria eggs were collected from the Kızılırmak Delta in Samsun Province, Türkiye, in May 2022. The 2nd instar larvae of M. neustria were divided into seven different groups: one control, three with varying concentrations of CuO NPs (40, 200, and 1000 mg/L), and the other three with different concentrations of ZnO NPs (40, 200, and 1000 mg/L). As a result of the study, it was determined that the amounts of MDA and GSH and the activities of NOX, SOD, and CAT of the larvae exposed to both nanoparticles were higher compared to the control. As a result of the study, it is indicated that oxidative stress occurs in the insect exposed to toxic nanoparticles, and the insect defends itself against these nanoparticles with both enzymatic and non-enzymatic defenses. It is suggested that these nanoparticles can be utilized to control insects.

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.

Aim: Zinc oxide (ZnO) and titanium oxide (TiO2) nanoparticles are used on a commercial scale in many countries. Despite numerous studies on the toxicity of nanoparticles, few have addressed their toxicity in edible grains. The aim of this study was to investigate the growth inhibition of ZnO and TiO2 nanoparticles on lentil, wheat, and bean seeds. Methods: The ZnO and TiO2 nanoparticles were investigated using transmission electron microscopy. Different concentrations of ZnO and TiO2 nanoparticles (0.1, 1, 10, 100, and 1000 mg/l) were prepared in distilled water for irrigation of lentil, wheat, and bean seeds. The seeds were irrigated three times a day for 8 consecutive days, with 3 ml of solution per irrigation. To determine the toxicity of nanoparticles, the number of germinated seeds was counted, and the stem lengths were measured using a caliper. Data were analyzed to calculate the 50% lethal concentration (LC50). Results: Exposure to all concentrations of both nanoparticles resulted in growth reduction in lentil seeds. Bean seeds showed decreased growth with ZnO nanoparticles and increased growth with TiO2. Wheat seeds exhibited both growth increases and decreases at nanoparticle concentrations. Conclusions: This study showed that the toxic effect of nanoparticles depends on both the type of nanoparticle and the seeds. Furthermore, the concentration of nanoparticles plays a significant role in their toxicity. Therefore, more research is needed to explore the effects of different nanoparticles on plants in various growth environments to better understand their toxic effects on plant organs and their impact on plant growth and development.

Enhancement of astaxanthin production in Haematococcus pluvialis using zinc oxide nanoparticles

In this work, we improved the electromechanical properties, electrostrictive behavior and energy-harvesting performance of poly(vinylidenefluoridene-hexafluoropropylene) P(VDF-HFP)/zinc oxide (ZnO) composite nanofibers. The main factor in increasing their electromechanical performance and harvesting power based on electrostrictive behavior is an improved coefficient with a modified crystallinity phase and tuning the polarizability of material. These blends were fabricated by using a simple electrospinning method with varied ZnO contents (0, 5, 10, 15 and 20 wt%). The effects of the ZnO nanoparticle size and content on the phase transformation, dielectric permittivity, strain response and vibration energy harvesting were investigated. The characteristics of these structures were evaluated utilizing SEM, EDX, XRD, FT-IR and DMA. The electrical properties of the fabrication samples were examined by LCR meter as a function of the concentration of the ZnO and frequency. The strain response from the electric field was observed by the photonic displacement apparatus and lock-in amplifier along the thickness direction at a low frequency of 1 Hz. Moreover, the energy conversion behavior was determined by an energy-harvesting setup measuring the current induced in the composite nanofibers. The results showed that the ZnO nanoparticles’ component effectively achieves a strain response and the energy-harvesting capabilities of these P(VDF-HFP)/ZnO composites nanofibers. The electrostriction coefficient tended to increase with a higher ZnO content and an increasing dielectric constant. The generated current increased with the ZnO content when the external electric field was applied at a vibration of 20 Hz. Consequently, the ZnO nanoparticles dispersed into electrostrictive P(VDF-HFP) nanofibers, which offer a large power density and excellent efficiency of energy harvesting.

Objective The objective of this in vitrostudy was to comparatively evaluate the antifungaland physical properties of tissue conditioner incorporated with nanoparticles (NPs) of different types and concentrations. Materials and methods A total of 198 tissue conditioner samples were used in this study. The samples were categorized into a control group, namely, tissue conditioner without NPs (Group 1), and test groups, namely, tissue conditioner incorporated with zinc oxide (ZnO) NPs (Group 2) andmagnesium oxide (MgO) NPs (Group 3). The antifungal properties and surface roughness of the samples were evaluated. The groups were further subdivided into seven subgroups: control (without NPs), 5% ZnO NPs, 10% ZnO NPs, 15% ZnO NPs, 3% MgO NPs, 5% MgO NPs, and 7% MgO NPs by weight. Surface roughness was measured using an optical profilometer,and antifungal activity was measured in terms of the diameter of the inhibition zone (DIZ) using the well diffusion method over seven days. Results The result showed that the 5%ZnO NPs subgroup had the lowest mean surface roughness, whereas the 15% ZnO NPs subgroup had the highest antifungal activity. Increasing the concentration of NPsincreased the antifungal property, and there was a steady decrease in DIZ from day one to day seven in all test groups. Conclusion Our results showed that the incorporation of various concentrations of ZnO and MgO NPs into tissue conditioner samples positively affected their physical and antifungal properties. The highest antifungal activity was found in the 15% ZnO NPs subgroup, and the lowest surface roughness was found in the 5% ZnO NPs subgroup.

Application of nanomaterials in plant regeneration of rice (Oryza sativa L.)

Flexural strength and surface hardness of nanocomposite denture base resins

In this work, metal/semiconductor nanocomposites/metal devices with aluminium (Al) as top electrode (TE) and bottom electrode (BE) were fabricated and investigated using ZnO nanoparticles (ZNPs) embedded in an insulating polyvinyl alcohol (PVA) matrix for non-volatile memory applications. The I-V measurements of Al/ZnO-PVA/Al device exhibited a non-volatile bistable resistive switching behaviour. The switching mechanism of the device was suggested by the models of trap controlled space-charge limited conduction (SCLC) and the charges trapping-detrapping process at the centers of ZNPs in the PVA matrix. The state of the device was maintained even after removal of the applied bias, indicating the non-volatile bistable memory. There was no remarkable degradation of the device in both the LRS and the HRS after 30 minutes continuous operation which demonstrated excellent stability of the device. The current ratio of high resistance state (HRS) to low resistance state (LRS) is about of the order of 102 at room temperature. This demonstration provides a class of memory devices for non-volatile bistable memory device applications.

The aim of this research was to investigate experimentally the performance and combustion characteristics of a four‐stroke, single‐cylinder, water‐cooled variable compression ratio diesel engine using rice bran oil biodiesel blends with zinc oxide nanoparticles. Rice bran oil biodiesel was prepared using a transesterification reaction with a 6:1 methanol‐oil molar ratio and 1% w/w potassium hydroxide as catalyst. Zinc oxide nanoparticles were synthesized using a green method incorporating Psidium guajava leaf extract as a capping agent to reduce precursor use and to reduce the toxicity of the nanomaterial. The synthesized zinc oxide nanoparticles were characterized by using X‐ray diffraction and Fourier‐transform infrared spectroscopy to confirm the formation of highly crystalline pure zinc oxide nanoparticles with a hexagonal wurtzite crystal structure with an average diameter of 20.963 nm. Rice bran‐oil biodiesel‐diesel blend was prepared by volumetrically mixing 20% biodiesel and 80% mineral diesel and was considered as a base fuel for comparison. Zinc oxide nanoparticles were diffused in the base fuel at dosage levels of 25, 50, and 75 ppm, with the aid of ultrasonication. Measurement of the major physicochemical properties of test fuels showed an increase in the cetane number and calorific value and a reduction in viscosity with an increase in the zinc oxide concentration. The overall properties of all the test fuels were found to be similar in comparison with commercial diesel. An experimental engine test was carried out under different loading conditions with a constant speed of 1500 RPM and two different compression ratios – that is, 17.5:1 and 15:1. Among all the test fuels at both compression ratios, engine performance and combustion properties improved with an increase in the zinc oxide concentration. Test fuel with 75 ppm of zinc oxide additive at 17.5 compression ratio resulted in an overall improvement at full load: brake thermal efficiency increased by 2.45%, brake specific fuel consumption reduced by 5.45%, cylinder peak pressure increased by 3.27% and net heat release increased by 10.32% in comparison with base fuel.

The appropriate combination of semiconducting polymer-inorganic nanocomposites can enhance the existing performance of polymers-only-based photovoltaic devices. Hence, polyaniline (PANI)/zinc oxide (ZnO) nanocomposites were prepared by combining ZnO nanoparticles with PANI in four distinct ratios to optimize their photovoltaic performance. Using a simple coating method, PANI, ZnO, and its nanocomposite, with varying weight percent (wt%) concentrations of ZnO nanoparticles, i.e., (1 wt%, 2 wt%, 3 wt%, and 4 wt%), were fabricated and utilized as an active layer to evaluate the potential for the high-power conversion efficiency of various concentrations, respectively. PANI/ZnO nanocomposites are characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), atomic force microscopy (AFM), Fourier transform infrared (FTIR) spectroscopy, ultraviolet-visible (UV-vis) absorption, energy dispersive X-ray (EDX), and I-V measurement techniques. The XRD analysis showed a distinct, narrow peak, which corresponds to the wurtzite ZnO (101) plane. The SEM analysis verified the production of the PANI/ZnO composite by demonstrating that the crystalline ZnO was integrated into the PANI matrix. The elemental composition was determined by energy dispersive X-ray analysis (EDX), which confirmed the existence of PANI and ZnO without any impurities, respectively. Using Fourier transform infrared (FTIR) spectroscopy, various chemical bonds and stretching vibrations were analyzed and assigned to different peaks. The bandgap narrowing with an increasing PANI/ZnO composition led to exceptional optical improvement. The I-V characterization was utilized to investigate the impact of the nanocomposite on the electrical properties of the PANI/ZnO, and various concentrations of ZnO (1 wt%, 2 wt%, 3 wt%, and 4 wt%) in the PANI matrix were analyzed under both light and dark conditions at an STC of 1.5 AM globally. A high PCE of 4.48% was achieved for the PANI/ZnO (3 wt%), which revealed that the conductivity of the PANI/ZnO nanocomposite thin films improved with the increasing nanocomposite concentration.

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.