Embedding Zinc Oxide Research Articles

Scalable, Waterproof, Breathable, and Flexible Polyolefin-Elastomer/Polyethylene Glycol@Zinc Oxide Microfibrous Fabrics for Daytime Radiative Cooling Clothing.

In the face of escalating global temperatures, the demand for innovative passive cooling technologies that are both low-cost and environmentally sustainable is more critical than ever. However, traditional cooling fabrics face challenges in achieving wearing comfort while maintaining breathability and durability. Herein, a novel fluffy microfibrous fabric utilizing polyolefin-elastomer and polypropylene with embedded zinc oxide nanoparticles is fabricated through melt-blown technology. The results reveal that the prepared samples demonstrate exceptional daytime radiative cooling properties that present a 12.5 °C cooling capacity under 1083 W/m2 solar radiation, highlighted by their ability to reflect up to 90.8% of solar radiation and their significantly enhanced thermal emissivity. Moreover, key findings include that the samples have robust mechanical strength, high elastic performance, and excellent antifouling capabilities, alongside superior cooling performance, which will provide an opportunity to explore the development of cooling garments for outdoor environments and contribute substantially to sustainable cooling solutions.

Piezoelectric PMS activation by ZnO embedded polytetrafluoroethylene membrane for efficient degradation of carbamazepine

The wide-spread micropollutants in water have posed severe risks to human health and eco-environment. However, the current treatment techniques generally suffer from low efficiency, high cost and unpractical application feasibility. In this study, a piezoelectric membrane was fabricated by embedding zinc oxide (ZnO) nanorods with several micrometer length into polytetrafluoroethylene nanofiber membrane and applied for the removal of carbamazepine (CBZ) from water. After the sintering, the prepared membrane showed a narrower pore size distribution with the average pore size of ∼1.7 µm. The addition of ZnO nanorods could significantly improve the piezoelectric property of the membrane. During the membrane filtration, the peroxymonosulfate could be effectively activated by the prepared piezoelectric membrane with 2 % ZnO dosage to generate free radicals, achieving about 83.1 % of CBZ from water. According to the radical quenching tests and electron spin-resonance analysis, the hydroxyl radical, sulfate radical, singlet oxygen and superoxide radical greatly participated in the CBZ removal. The CBZ removal efficiency in the US/PMS/PTFE@ZnO-2 system was decreased by 18.2 % after continuous 5-cycle operation, but the performance could be easily renewed by methanol rinsing, demonstrating its attractive reusability and application potential on the efficient removal of micropollutants from water.

The interface design and properties enhancement of ZnO/cellulose composites: Branching fiber network to guide the assembly of ZnO flower

Using renewable biomass resources to regulate the growth and properties of catalysts is sustainable nanotechnology for achieving efficient photocatalysis and recycling. This work suggested a way to produce paper-based photocatalysts and resize the embedded zinc oxide (ZnO) flowers. The combination of experimental analysis and theoretical simulations demonstrated that small pores of the branching fiber network enhanced the interfacial interaction between ZnO flowers and cellulose fibers, thereby improving mechanical properties and optimizing flower structure. The interaction energy and electron density difference (EDD) simulation results demonstrated that the ZnO/cellulose interface structure shares significant attraction and charge transfer. Cellulose fibers ground for 20 cycles (CFG20) possessed dense branching fiber network and loaded with the smallest ZnO flowers, achieving a balance of strong mechanical properties and reaction efficiency. Remarkably, ZnO/CFG20 paper-based catalyst indicated strong photodegradation efficiency (100% for methyl orange, 100% for phenol, and 85.23% for aniline) and excellent reusability. This work will pave the way for the green regulation of catalysts.

Fabrication of silver nanodome embedded zinc oxide nanorods for enhanced Raman spectroscopy

Herein, we demonstrate a facile and versatile method to decorate various sizes of silver nanodomes (ZnONR@AgND) along the length of zinc oxide nanorods (AgND) grown over fluorine-doped tin oxide (FTO) substrate. The silver nanodomes (AgND) embedded along the edges of hexagonal zinc oxide nanorods/FTO (ZnONR) substrate were fabricated by using a combination of size selective ZnONR growth and thermal reconstruction. The prepared heterostructure's structural, morphological, and optical behaviors were analyzed by Transmission electron microscopy (TEM), X-Ray diffraction, Raman spectroscopy, field emission scanning electron microscopy (FE-SEM), and UV-Vis spectroscopy. The results confirm the formation of ZnONR@AgND heterostructure with close-packing and construction of the crystalline AgND, adhering to the different faces of the 1D semiconducting ZnONR rods. The AgND size and separation was controlled by the initial sputter thickness and the thermal budget employed during annealing. Insight into the enhanced mechanism for surface-enhanced raman scattering (SERS) activity of ZnONR@AgND was ascertained by probing the hot-spot localization and the enhancement in the electric field by COMSOL simulations and experimentally verified by using rhodamine 6 G (R6G) probe molecules at various concentration 10−3 − 10−12 M. The prepared ZnONR@AgND demonstrated a superior SERS signal (~10 times) due to localization of the hot spots at the AgNDs compared to pure Ag nanoparticles substrate (for 10−6 M). The improved SERS performance of the ZnONR@AgND is attributed to an effective charge transport within the plasmonic AgND, semiconducting ZnO, and the R6G molecule facilitated by the ability of the heterostructure to accommodate multiple hot-spots in a limited volume. This work demonstrates that the SERS activity of semiconductor-based hybrid Raman substrate can be significantly improved by effectively tuning the metal nanoparticle size and density along the length of such hybrid nanowires.

Effect of Polyethylene Film Thickness on the Antimicrobial Activity of Embedded Zinc Oxide Nanoparticles.

Microbial contamination of most foods occurs primarily at the surface during postprocessing and handling; therefore, preventing cross-contamination by incorporation of antimicrobial substances in contact with the surface of the product is an efficient strategy in reducing food contamination risks. Zinc oxide nanoparticles (ZnONPs) have been used widely to achieve antimicrobial films in various applications including the food industry. This work describes the fabrication of antimicrobial polymeric films containing ZnONPs produced by the coextrusion and dip-coating techniques. Effects of skin layer thicknesses containing ZnONPs on the antimicrobial effectiveness of the film by their capability to inactivate Gram-positive and Gram-negative bacteria were studied for both methods. The antimicrobial properties of the coextruded multilayer LLDPE/ZnONP nanocomposite films evidenced antimicrobial activity in the range 0.5–1.5 log reductions, while in the case of a sandblasted multilayer film, it showed high antimicrobial properties as around 99.99%. The optical properties of coextruded multilayer films were measured and discussed. Furthermore, to achieve a thinner LLDPE thickness, ZnONPs were coated with different concentrations of LLDPE solution by the dip-coating method. TEM confirmed that a homogeneous layer is formed on the surface of ZnONPs. The thickness of the LLDPE layer estimated by TEM was about 2 nm and film produced 3 log and 4 log reductions for E. coli and S. aureus, respectively. The results show that developed films have the potential to be used as food packaging films and can extend shelf life, maintain quality, and assure the safety of food. The antimicrobial mechanisms of ZnONPs were also investigated. It was found that direct contact of particles with products is necessary to assure high antibacterial activity of the films.

Low‐frequency nanocomposite piezoelectric energy harvester with embedded zinc oxide nanowires

AbstractSweeping developments in microelectromechanical systems and low power electronics have pushed the need for piezoelectric energy harvesters (PEHs). Increasing environmental and biocompatibility issues have drawn interest in lead‐free piezoelectric materials. In this paper, cantilever‐type PEHs at centimeter scale have been proposed to harvest the energies of low‐frequency vibrations caused by a human's movements. The proposed PEHs are made of a passive PDMS substrate sandwiched between two active nanocomposite layers with embedded piezoelectric zinc oxide (ZnO) nanowires. Moreover, two different morphologies including PEHs with constant and tapered thicknesses have been considered. The material properties of such piezoelectric nanocomposites are calculated by an electromechanical model. Afterward, these novel PEHs have been developed in COMSOL Multiphysics and their static and dynamic performances have been investigated. The static study shows that tapered PEHs endures lower stresses. However, the dynamic study discloses that the rectangular design outperforms the tapered one in electrical power and resonance frequency. It is found that the rectangular design can produce 4.1623 μW at the resonant frequency of 25.8 Hz.

ZnO NPs incorporated gelatin grafted polyacrylamide hydrogel nanocomposite for controlled release of ciprofloxacin

Hydrogel nanocomposites are hydrogels which are equipped with nanomaterial within their polymeric framework. They exhibit superior strength and elasticity compared to conventional hydrogels. The present work focuses to develop a new gelatin based hydrogel nanocomposite by embedding zinc oxide nanoparticles (ZnO NPs) within gelatin-polyacrylamide hydrogel, for the controlled release of ciprofloxacin (CFX). The synthesized ZnO NPs, gelatin polyacrylamide hydrogel (GAm) and hydrogel nanocomposite (GAmZ) have been characterized using various techniques. The swelling and in vitro CFX release studies revealed that incorporation of ZnO NPs in the hydrogel matrix has not only improved the swelling characteristics and thermal stability of the hydrogel matrix but also exhibited more controlled and pH dependent release of CFX. The drug release kinetic study has revealed that the system exhibited zero order kinetics and followed the Super case II transport mechanism for CFX release.

Zinc oxide nanowires‐based flexible pressure sensor

Embedding piezoelectric nanowires within a soft elastomer material should provide a superior pressure sensing transducer, exploiting the piezoelectric properties of the nanowire material while maintaining flexibility. Here, a flexible sensor has been fabricated on a Kapton substrate and has incorporated a layer of polydimethylsiloxane with embedded zinc oxide nanowires as the pressure sensing mechanism. In response to applied compressive pressure up to 127 kPa, the device has generated a voltage, between electrodes on either side of the nanowire/polydimethylsiloxane layer, with a sensitivity of 23.6 mV/kPa, which is 100 times greater than previously reported zinc oxide nanostructure-based flexible sensors.

Rationally embedded zinc oxide nanospheres serving as electron transport channels in bismuth vanadate/zinc oxide heterostructures for improved photoelectrochemical efficiency

In this work, we demonstrate the fabrication of Mo, W co-doped BiVO4/ZnO nanosphere (Mo, W: BVO/ZnO NS) heterostructures using a simple solution dry-out method that uniformly embeds ZnO NSs in Mo, W: BVO nanocrystals. Photoelectrochemical (PEC) examination confirmed that Mo, W: BVO/ZnO NSs exhibit higher PEC performance than pure Mo, W: BVO, and this improved performance of Mo, W: BVO/ZnO NSs also depends on decreased ZnO NS size. Moreover, a layered ZnO/Mo, W: BVO (ZnO film coated with Mo, W: BVO layer) heterostructure was prepared using a simple physical piled method that exhibited far lower PEC performances than those of Mo, W: BVO/ZnO NS heterostructures. These results clearly revealed that the formation of the Mo, W: BVO/ZnO NS heterostructure could increase the charge carrier density and it possessed a much larger contact area. These improvements were favorable for the transfer and transport of photoexcited charge carriers. This work offers an effective strategy to fabricate heterostructures with effective charge separation by a simple solution dry-out method that is suitable for other heterostructure-engineered photoanodes in solar water-splitting applications.

Nanocomposite alginate-based electrospun membranes as novel adsorbent systems

Alginate-based membranes embedding zinc oxide nanoparticles are prepared via electrospinning and exploited as biosorbent materials. The mats exhibit a uniform texture characterized by the presence of nanofibers with an average diameter of 100 nm and interconnected voids of 140 nm average size. UV–vis spectrophotometric tests were performed to evaluate the membrane uptake/release performances by employing aqueous solutions of Methylene Blue (MB) and Congo Red (CR), chosen as model probes of basic and acidic type, respectively. Isotherm kinetics and equilibrium data are fitted with theoretical models to acquire information on the process mechanisms and rates. At low dosage, the mats show comparable adsorption capacity toward both dyes with limited selectivity for the cationic one suggesting that the process is conditioned by the macroporous structure of the membranes. Moreover, a good reusability for achieved for MB after simple washing steps in deionized water. Remarkably, the desorption efficacy under physiological-like conditions turn out to be very high for MB but reduced for CR indicating that the release process is affected by ionic interactions. Based on the results, the electrospun membranes reveal potential as innovative, low-cost, and versatile absorbent platforms to be used in drug delivery applications as well as in purification processes.

Corrosion behavior of novel AA1050/ZnO surface composite: A potential material for ship hull

Friction stir processing is one of the effective surface treatments which was employed to process the AA1050 sheets in bare and reinforced condition. The primary objective of the investigation was to expand the applications of AA1050 as a ship hull element in shipbuilding with the least corrosion rate to withstand the harsh marine environment. The base material processed with a rotational speed of 1200 rpm resulted in the highest corrosion rate of 0.173622 mpy. The formation of Al-Fe intermetallic phases was responsible for pitting corrosion. Further, processing by embedding zinc oxide with a rotational speed of 1000 rpm exhibited ~6.68 times improvement in corrosion resistance compared to as-received material. The corrosion rate was found to be 0.003390 mpy. The Al2O3 passive film hinders the initiation and propagation of pits. This study coins a novel composite material and future investigations are emphasized on the same lines.

Preparation of composite alginate-based electrospun membranes loaded with ZnO nanoparticles

In the present work alginate-based nanofibrous membranes embedding zinc oxide nanoparticles (ZnO-NPs) were prepared via electrospinning technique. ZnO-NPs were synthesized by means of a “green” sol-gel method by using alginate itself as stabilizing agent and characterized through UV–vis spectroscopy, thermogravimetric and morphological analysis. Formulations containing sodium alginate, poly(ethylene oxide) and ZnO-NPs were rheologically studied to identify the most suitable ones to be electrospun; alginate molecular structure played an important role on the solution spinnability due to the polysaccharide capability to establish electrostatic interactions and hydrogen bonds with ZnO-NPs. An innovative washing-crosslinking protocol was developed to obtain stable products which composition was assessed using Fourier Transform InfraRed spectroscopy and thermogravimetric analysis. Morphological investigation combined with EDX spectroscopy proved the obtained mats were highly porous and composed by thin homogenous nanofibers with a good distribution of the used nanofillers, thus representing potential products for several purposes (e.g. biomedical, pharmaceutical and environmental applications).

Preparation and application of zinc oxide/poly(m‐phenylene isophthalamide) hybrid ultrafiltration membranes

ABSTRACTA small molecular‐weight cut‐off (MWCO) of 6000 Da poly(m‐phenylene isophthalamide) (PMIA) embedded zinc oxide (ZnO) hybrid ultrafiltration (UF) membrane was synthesized via nonsolvent‐induced phase separation (NIPS). Tests of field emission scanning electron microscope (FE‐SEM), energy dispersive X‐ray spectroscopy (EDX), atomic force microscopy (AFM), thermal gravimetric analyzer (TGA), Fourier transform infrared (FTIR), capillary flow porometer (CPF), mechanical test, and pure water flux (PWF) for characterization of membranes were carried out. The EDX, FTIR, and TGA indicated the presence of ZnO in the polymer matrix. The hybrid membranes showed enhanced pore density, PWF by the presence of the particles. The contact angle and water flux of modified membrane with 0.03 wt % of nano‐ZnO were 47.7° and 52.58 L·m−2·h−1compared to 71.6° and 36.27 L·m−2·h−1respectively; Compared with the hydrophobic membrane, the PMIA membrane, with hydrophilicity, is supposed to exhibit good antifouling properties. Furthermore, the thermal stability and mechanical properties of the modified membranes were increased. Finally, the hybrid membrane was used in treating papermaking white wastewater and exhibited good separation and high water flux. The great properties of the ultrafiltration PMIA membranes indicate their potential for excellent performance in industrial applications. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2019,136, 47583.

Generation of four-wave mixing with highly sharp idlers using 2 mm home-made side-polished fiber deposited by ZnO nanorod

A side-polished fiber with embedded zinc oxide nanorods (ZnO-NRs) is proposed, fabricated, and tested to generate four-wave-mixing (FWM). The side-polished fiber is manufactured by polishing a conventional single mode fiber to completely remove 2 mm of its cladding and its core partially, after which the fiber is simply immersed into a solution consisting of ZnO-NRs and allowing it to dry. A pump and a signal wavelength of 1550 and 1551 nm are injected into the fiber and generate idlers at 1549 and 1552 nm which agree well with theoretical values. Our experimental results show that the optimum FWM range is determined to be a 6 nm shifted away from the pump wavelength and occurs in the pump and wavelength spacing as narrow as 0.1 nm. The proposed system allows for the easy integration of optically active materials into a fiber.

One step biofunctionalized electrospun multiwalled carbon nanotubes embedded zinc oxide nanowire interface for highly sensitive detection of carcinoma antigen-125

Ovarian cancer is the most leading cause of cancer-related death in women . The carcinoma antigen-125, which is found on the surface of many ovarian cancer cells is known to be a gold standard clinical biomarker associated with life-threatening gynecological malignancy. In this work, we demonstrate a novel biosensor platform based on multiwalled carbon nanotubes embedded zinc oxide nanowire for the ultrasensitive detection of carcinoma antigen-125. Label free detection of the carcinoma antigen-125 was accomplished by differential voltammetry technique that demonstrated excellent sensitivity (90.14µA/(U/mL)/cm2) with a detection limit of 0.00113UmL−1 concentration. The fabricated immunosensor exhibits good performance with wider detection range (0.001UmL−1–1kUmL−1), reproducibility, selectivity, acceptable stability, and thus is a potential cost-effective methodology for point-of-care diagnosis. The multiwalled carbon nanotubes (MWCNTs) embedded highly oriented zinc oxide (ZnO) nanowires were synthesized by simple, low cost electrospinning technique. Compared to pure ZnO nanowires, electrochemical activity of MWCNTs embedded ZnO nanowires was found to be much higher. The calcination temperature was optimized to avoid any decomposition of the CNTs and to obtain multiwalled carbon nanotubes embedded highly crystalline ZnO nanowires. The salient feature of this biosensing platform is that one step calcination process is enough to create the functional groups on MWCNT-ZnO nanowire surface that are effective for the covalent conjugation of antibody without further surface modification. To the best of our knowledge, this is the first report on MWCNT-ZnO nanowire based immunosensor explored for the detection of cancer biomarker.

Enhanced ionic polymer metal composite actuator with porous nafion membrane using zinc oxide particulate leaching method

In this study, to improve the performance of an ionic polymer metal composite (IPMC), we suggest a porous nafion membrane fabricated with the particulate leaching method with zinc oxide and propose an IPMC that uses the porous nafion membrane. To fabricate this membrane, the proper ratio of nafion and zinc oxide powder is dispersed in a solvent. Then the zinc oxide embedded in the nafion membrane is fabricated with a casting method. With the particulate leaching method, the embedded zinc oxide particles are dissolved by an acid solution, and the spaces of the zinc oxide particles changed to pores. Finally, through electroless plating and ion exchange procedures, an IPMC with the porous nafion membrane is fabricated. The proposed IPMC has higher water uptake (WUP) and ion exchange capacity (IEC) and can show better actuation performance compared to the conventional nafion-based IPMC. We also measure the actuation displacement and blocking forces of the proposed IPMC. Compared with the conventional nafion-based IPMC, the proposed IPMC with the porous nafion membrane has increased displacements: about 80% at ac input and about 250% at dc input, and increased blocking force about 130% at dc input.

Active sensing and damage detection using piezoelectric zinc oxide-based nanocomposites

This study investigated the design and performance of piezoelectric nanocomposite-based interdigitated transducers (IDTs) for active sensing and damage detection. First, thin films that are highly piezoelectric and mechanically flexible were designed by embedding zinc oxide (ZnO) nanoparticles in a poly(vinylidene fluoride–trifluoroethylene) (PVDF–TrFE) piezo-polymer matrix. Second, the suspended nanoparticle solutions were then spin coated onto patterned comb electrodes to fabricate the IDTs. The films were then poled to align their electric domains and to increase their permanent piezoelectricity. Upon IDT fabrication, its sensing and actuation of Lamb waves on an aluminum pipe was validated. These results were also compared to data obtained from commercial Macro Fiber Composite IDT transducers. In the last phase of this work, damage detection was demonstrated by mounting these nanocomposite sensors and actuators (using a pitch-catch setup) onto an aluminum pipe and plate. Damage was simulated by tightening a band clamp around the pipe and by drilling holes in the plate. A damage index calculation was used to compare results corresponding to different levels of damage applied to the plate (i.e., different drilled hole depths), and good correlation was observed. Thus, ZnO/PVDF–TrFE transducers were shown to have the potential for use as piezoelectric transducers for structural health monitoring and damage detection.

Photoluminescence of ZnO infiltrated into a three-dimensional photonic crystal

The effect of the photonic band gap (stopband) of the photonic crystal, the synthesized SiO2 opal with embedded zinc oxide, on its luminescence in the violet spectral region is studied. It is shown that the position of the photonic band gap in the luminescence and reflectance spectra of the infiltrated opal depends on the diameter of the constituent nanoglobules, the volume fraction of zinc oxide, and on the signal’s acceptance angle. It is found that, for the ZnO-opal nanocomposites, the emission intensity is decreased and the luminescence decay time is increased in the spatial directions, in which the photonic band gap coincides in spectral position with the luminescence peak of zinc oxide. The change in the decay time can be attributed to the change in the local density of photonic states in the photonic band gap.