Nanocomposite Foils Research Articles

Nanocomposite Foils of PS/Cu : Dual Functionality of Optical Enhancement and Antibacterial Activity on Aeromonas hydrophila

Nanocomposite Foils of PS/Cu : Dual Functionality of Optical Enhancement and Antibacterial Activity on Aeromonas hydrophila

Fabrication of Ni–ZrO2 nanocomposites through a new electroforming bath and Assessment of their morphology, wear, and corrosion resistance

Nowadays, researchers are looking for ways to produce complex tools and pieces with high precision at a low cost. In recent decades, electroforming has been an important and stable technique for producing composite parts. In this research, Ni–ZrO2 nanocomposite foils were fabricated by using a nickel-chloride bath through electroforming, a bath not previously utilized for this purpose. In this study, the effects of ZrO2 concentration and direct current density on the volume percentage of ZrO2 nanoparticles and the grain size of the nickel matrix of foils are also investigated. The sample with 13.65 vol % nanoparticles had the highest volume percentage and the minimum nickel grain size of 516.9 nm, which is almost 46 % smaller than the grain size of pure nickel foil. The wear and corrosion behavior of the foils were examined using a pin-on-disk wear test, potentiodynamic polarization, and impedance spectroscopy analysis. The results showed considerable improvement in the wear and corrosion resistance of the Ni–ZrO2 samples compared to the pure electroformed nickel. The nanocomposites exhibit a lower friction coefficient than pure nickel, with a maximum reduction of 44 %. A composite specimen of Ni–ZrO2 had 2.5 % lower corrosion density and 596 % higher charge transfer resistance compared to pure nickel. It was concluded that the nickel-chloride bath has an excellent potential to produce composite nickel foils with acceptable brightness, satisfactory wear, and corrosion resistance.

Energy band gap investigation of Al nanoparticles/polystyrene nanocomposite foils

Energy band gap investigation of Al nanoparticles/polystyrene nanocomposite foils

Nonlinear optical characteristics and optical limiting performance of copper nanoparticles embedded polystyrene nanocomposite foils for photonic application

Nonlinear optical characteristics and optical limiting performance of copper nanoparticles embedded polystyrene nanocomposite foils for photonic application

Eco-Friendly Photoactive Foils Based on ZnO/SnO2-PMMA Nanocomposites with High Reuse Potential

In the last decades, water pollution from different industries has been one of the largest environmental issues. Many efforts have been made to develop technologies to remove toxic pollutants from the contaminated waters, which are direct threats to the aquatic environment and human health. Among different technologies, heterogeneous catalysis has shown to be very effective for water purification. The main issue regarding this method is the water recovery after the treatment, which is a very expensive and laborious procedure but can be addressed by the immobilization of photocatalytic particles on the support material. Here, we present efficient and green technology for water purification based on ZnO/SnO2-poly(methyl methacrylate) (PMMA) nanocomposite foils utilizing superior photocatalytic properties of coupled ZnO and SnO2 photocatalysts. We investigated the influence of the ZnO/SnO2 nanoparticle concentration on the removal efficiency of methylene blue dye and found exceptional removal efficiency for even very low ZnO/SnO2 nanoparticle loadings. The investigated foils were found to be highly reusable, with no change in performance after five successive usages. The composition, optical properties, surface morphology, and surface roughness of the foils were characterized by X-ray diffraction, UV–vis spectroscopy, scanning electron microscopy, and atomic force microscopy. The thermal measurements performed with differential scanning calorimetry suggested the reinforcement effect of ZnO/SnO2 nanoparticles on the PMMA matrix, which is essential for practical applications of the foils.

Optical and Dispersion Energy Parameters of PS/Ag Nanocomposite Foils and Their Antibacterial Activity Against MDR Bacteria

Optical and Dispersion Energy Parameters of PS/Ag Nanocomposite Foils and Their Antibacterial Activity Against MDR Bacteria

Estimation of structural and optical properties of transparent PS/ZnO nanocomposite foils for UV shielding and photonic applications

The structural and optical characteristics of polystyrene (PS) and ZnO nanoparticles embedded in polystyrene as polymeric nanocomposite foils (PS/ZnO) were examined. The sol–gel process was utilized to make ZnO nanoparticles with a diameter of less than 50 nm. The solution casting process was used to prepare pure PS and PS/ZnO nanocomposite foils. The PS/ZnO nanocomposite foils were very transparent in the visible region as-synthesized, but due to substantial absorption in the UV area, absorbent peaks were formed at 264 nm and 364 nm, and these foils serve as UV absorbers. X-ray diffractometer (XRD) of ZnO embedded polystyrene nanocomposite foils studied the crystal structure of the flexible foils. Optical properties and optical constants including band gap were studied by transmittance, absorbance, and reflectance spectra that are obtained by UV–Vis spectrophotometer. The Wemple DiDomenico single oscillator model was used to estimate the dispersion energy parameters ([Formula: see text], [Formula: see text], [Formula: see text], optical moments ([Formula: see text], [Formula: see text], the density of states ([Formula: see text]/[Formula: see text]), dispersion of refractive index ([Formula: see text], and plasma frequency ([Formula: see text] of the investigated foils. Semi-empirical relations were used to estimate the nonlinear index of refraction ([Formula: see text] and third-order optical nonlinear susceptibility ([Formula: see text]. PS/ZnO nanocomposite foils operate as UV absorbents and are a promising preference for photonic applications due to their optical characteristics.

Third order nonlinearity and optical power limiting studies of PS/ZnO nanocomposite foils for photonic applications

The present work focuses on the preparation of Polystyrene (PS) and PS/ZnO nanocomposite foils by solution casting method and study their structural and nonlinear optical (NLO) characterizations. The Zinc Oxide (ZnO) nanoparticles were synthesized by Sol-gel method. Structural analysis of the prepared nanocomposite foils was carried out by x-ray diffraction (XRD) with an estimated average crystallite size of 27.33 nm. UV–vis-NIR spectra reveal that the nanocomposite foils are transparent in the visible region. FESEM micrographs show the surface morphology of the prepared nanocomposite foils. Energy Dispersive x-ray Spectroscopy (EDX) of the prepared foils confirmed the compositional and spatial distribution of the elements. The NLO properties such as nonlinear absorption coefficient (β), nonlinear index of refraction (n2), and third-order nonlinear susceptibility were investigated by Z-scan technique at a wavelength of 532 nm and 200 mW with field intensity The values of β were found to bein the order of ∼ 10−7 cm W−1, n2 in the order of ∼10−12 cm2 W−1 and in the range 4.99 × 10−7– 38.7 × 10−7e.s.u. Further, the optical power limiting threshold was calculated to be 3.646 KW cm−2 for 8 wt % of PS/ZnO nanocomposite foil which is a better candidate to act as an optical limiter. The figure of merit has also been determined that establishes the suitability of nanocomposite foils for optical limiting and/or optical switching applications in the visible region.

Investigation of optical energy band gap of transition metal oxide/polystyrene nanocomposite foils

In the present work, the optical properties of pure polystyrene, ZnO and AgO nanoparticles embedded polymeric foils were investigated. ZnO nanoparticles and AgO nanoparticles having size less than 50 nm were used. Pure polystyrene and ZnO, AgO nanoparticles embedded polystyrene foils were prepared by solution casting method. The investigated nanocomposite polymeric foils were highly transparent in the visible region, but due to strong absorbance in the UV region, absorbent peaks obtained at 364 nm and 250 nm, these foils act as an absorber in the UV region. PS/ZnO nanocomposite foils were characterized by transmittance and absorbance data that were obtained by UV–VIS spectrophotometer. The most important application of these foils is found to be in UV shielding and also based on the optical properties such as optical energy band was investigated, the PS/ZnO nanocomposite foils act as UV absorbent and a potential candidate for optoelectronic applications.

Formation and Investigation of Physicochemical, Biological and Bacteriostatic Properties of Nanocomposite Foils Containing Silver Nanoparticles and Graphene Oxide in Hyaluronic Acid Matrix.

Natural polysaccharides, including hyaluronic acid, find a wide range of applications in biomedical sciences. There is a growing interest in nanocomposites containing hyaluronic acid and nanoparticles such as nanometals or graphene. In this study, we prepared foils of pure sodium hyaluronate and sodium hyaluronate containing nanosilver, graphene oxide, nanosilver/graphene oxide and characterized their properties. UV-vis spectroscopy and scanning electron microscopy (SEM) confirmed the formation of 10–20 nm silver nanoparticles. The structural changes were investigated using Fourier transforms infrared (FTIR) spectra and size exclusion chromatography. The obtained results suggest changes in molecular weights in the samples containing nanoparticles, which was highest in a sample containing nanosilver/graphene oxide. We also assessed the mechanical properties of the foils (thickness, tensile strength and elongation at break) and their wettability. The foils containing nanosilver and nanosilver/graphene oxide presented bacteriostatic activity against E. coli, Staphylococcus spp. and Bacillus spp., which was not observed in the control and sample containing graphene oxide. The composites containing graphene oxide and nanosilver/graphene oxide exhibited a cytotoxic effect on human melanoma WM266-4 cell lines (ATCC, Manassas, VA, USA).

Effect of a high magnetic field on hard magnetic multilayered Fe-Pt alloys

Abstract Fe-50 vol%Pt multilayers that were prepared by accumulative roll-bonding were annealed in vacuum for 2 h at various temperatures between 723 K and 823 K. Some samples were annealed without any high magnetic field (HMF). Others were subjected HMF up to 31.2 T, applied in either in-plane or out-of-plane directions. The annealing partially transformed the original multilayered structure into a polycrystalline hard-magnetic FePt magnetic phase with ordered L10 structure. Textured FePt/Fe nanocomposite foils were formed under HMF. Magnetic anisotropic behavior was observed in the annealed FePt/Fe composite because of the textured nanostructure. HMF annealing decreased grain size and increased the (0 0 1) texture along the HMF direction. In the sample annealed with out-of-plane HMF, both coercivity and maximum energy product were enhanced because of higher (0 0 1) out-of-plane texture and finer nanoscaled grain sizes compared to other samples. An in-plane HMF appeared to strongly inhibit phase transformation. This inhibition likely resulted from a change in Gibbs free energy and the diffusion inhibition caused by HMF.

The influence of sample thickness on the combustion of Al:Zr and Al-8Mg:Zr nanolaminate foils

Al:Zr and Al-8Mg:Zr nanocomposite foils do not combust completely in air because the penetration of oxygen and nitrogen into the foils can become limited as the product phases grow. The heat produced during the combustion of these foils could feasibly depend upon the volume fraction of the surface oxide layer that forms and therefore the initial foil thickness as well. To test this, Al:Zr and Al-8Mg:Zr foils of various thicknesses (9–61 µm) were fabricated by Physical Vapor Deposition and their heats of combustion were measured using bomb calorimetry in 1 atm of air. We found that combustion efficiency decreased significantly for Al:Zr foils as thickness increased, but Al-8Mg:Zr foils had a nearly constant combustion efficiency for the range of thicknesses studied. SEM-EDS measurements across the foil cross-sections showed that for Al:Zr foils, a distinct oxide layer formed on the external surfaces and there were low levels of oxygen and nitrogen toward their centers. For Al-8Mg:Zr foils though, there was minimal dependence between heat output and foil thickness, the surface oxide layer was more diffuse, and the oxygen and nitrogen contents were higher throughout the foil. We propose that the addition of magnesium improves heat generation by increasing the rates of oxygen and nitrogen diffusion and thus enabling the formation of solid solutions that are richer in oxygen and nitrogen throughout the bulk of the foils.

Drawability and size effects for micro-arrayed deep drawing of Ni-Co/GO nanocomposite foils

For the first time, three different male dies (a rigid male die, an aluminum male die, and a nanoceramic powder male die) are used for a micro-arrayed deep drawing process using graphene oxide (GO) reinforced Ni-Co nanocomposite. Micro-parts with different shapes can be formed using the different male dies, and models to predict crack positions are established. The nanocomposite size effect leads to an increased depth-diameter ratio for decreasing female die diameters, and the conservation of volume leads to higher depth-diameter ratios and thinning rates. The reinforcing GO phase not only is able to improve the micro formability of the composite, but also inhibits grain growth at high temperature.

Process Optimization for Pulse Reverse Electrodeposition of Graphene-Reinforced Copper Nanocomposites

In the present study, processing of graphene-reinforced copper nanocomposite foils with homogenous dispersion of graphene throughout the matrix, exhibiting good mechanical properties by a simple, cost-effective, and scalable pulse reverse electrodeposition technique (PRED) with special focus on the influence of graphene content in the electrolyte to tailor the properties. A systematic approach has been adopted for enhancing the properties. Distribution of graphene nanosheets in the copper metal matrix and the microstructural properties have been studied by transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM). Interesting observations have been made from nanoindentation studies, where hardness (∼2.7 GPa) enhanced mainly with increase in graphene content (0–0.75 g/L), while maximum elastic modulus (∼139 GPa) is achieved for a graphene content of 0.5 g/L in the electrolyte. Four-point probe testing has been adopted to evaluate the electrical features. The major contribution in enhancement of properties is found to be the presence of graphene and its uniform individual dispersion and distribution as nanosheets in the copper matrix.

Design and functionality of a high-sensitivity bomb calorimeter specialized for reactive metallic foils

We have designed and built a unique non-adiabatic bomb calorimeter to measure heat generated from intermetallic formation reactions and the subsequent partial combustion of nanocomposite metallic foils. Reactions are initiated with a low-energy electrical spark and can be performed in 1 atm of air, oxygen, nitrogen, or argon, in order to investigate reaction and burning characteristics in various environments. The bomb was designed to hold the foil samples with minimal thermal contact in order to mitigate heat losses and maximize surface area available for oxidation and nitridation. Samples are limited to the milligram range, and are much less energetic than an equivalent mass of organic material such as benzoic acid. Therefore, to maximize instrument sensitivity, heat capacity was minimized by designing the bomb to be as small as possible and by using low-viscosity silicone oil for the bath instead of water. The calorimeter has an energy equivalent of e (calor) = 279 ± 6 J K−1, allowing us to measure heat generation on the order of tens of Joules. Calibrations were performed in argon using Al:Ni nanocomposite foils with well-known heats of reaction, which were measured using differential scanning calorimetry.

Using magnesium to maximize heat generated by reactive Al/Zr nanolaminates

In this study, we explore the effect of magnesium content on the ability of reactive nanocomposite foils to generate heat, by comparing three chemistries: Al:Zr, Al–8Mg:Zr, and Al–38Mg:Zr. These correspond to foils with alternating aluminum and zirconium layers where the Al is either pure, an 8at.%Mg alloy, or a 38at.%Mg alloy, respectively. Measurements performed in a specially designed bomb calorimeter show that Al–8Mg:Zr foils perform the best, generating the greatest gravimetric heat in air, oxygen, and nitrogen environments. Both Mg-containing foils release a visible plume of particles and vapor upon reacting, which was recorded with a high speed camera. This ejected mass includes Mg vapor and particles of all three metals. Both the vapor and particles oxidize rapidly in air, resulting in single metal-oxide particles. The reacted foils, particularly the Al–8Mg:Zr samples, contain voids and higher levels of oxygen and nitrogen throughout their thicknesses than reacted Al:Zr foils. To explain the higher heats of reaction for the Al–8Mg:Zr foils, we suggest that the out-diffusion and evaporation of Mg generates a high concentration of vacancies that enhance oxygen and nitrogen diffusion throughout the foil, thereby increasing the degree of oxidation and nitridation.

A New Electrochemical Approach for the Synthesis of Copper-Graphene Nanocomposite Foils with High Hardness

Graphene has proved its significant role as a reinforcement material in improving the strength of polymers as well as metal matrix composites due to its excellent mechanical properties. In addition, graphene is also shown to block dislocation motion in a nanolayered metal-graphene composites resulting in ultra high strength. In the present paper, we demonstrate the synthesis of very hard Cu-Graphene composite foils by a simple, scalable and economical pulse reverse electrodeposition method with a well designed pulse profile. Optimization of pulse parameters and current density resulted in composite foils with well dispersed graphene, exhibiting a high hardness of ~2.5 GPa and an increased elastic modulus of ~137 GPa while exhibiting an electrical conductivity comparable to that of pure Cu. The pulse parameters are designed in such a way to have finer grain size of Cu matrix as well as uniform dispersion of graphene throughout the matrix, contributing to high hardness and modulus. Annealing of these nanocomposite foils at 300°C, neither causes grain growth of the Cu matrix nor deteriorates the mechanical properties, indicating the role of graphene as an excellent reinforcement material as well as a grain growth inhibitor.

Advanced Rolling Technologies for Producing Ultrafine-grain/nanostructured Alloys

Ultrafine-grained materials show high strength at ambient temperature, high-speed superplastic deformation at elevated temperatures, and high corrosion resistance. Such materials have attracted increasing attention in the past twenty years. A number of severe plastic deformation techniques, such as equal-channel angular press, high pressure torsion, groove pressing, twist extrusion, asymmetric rolling, and accumulative roll bonding have been used to develop ultrafine-grained bulk materials. The equal-channel angular press, high pressure torsion, twist extrusion and groove pressing techniques suffer from some drawbacks: firstly, forming machines with large load capacities and expensive dies are indispensable for these processes; secondly, the productivity is relatively very limited; thirdly, the techniques are only suitable for small samples. Compared with equal-channel angular press, high pressure torsion, twist extrusion and groove pressing, the accumulative roll bonding and asymmetric rolling techniques can be used to produce continuous ultrafine-grained sheets in large quantities. In this paper, a survey of relatively recent rolling technologies is presented. The merits and drawbacks of each technique are examined. These techniques are: (1) Asymmetric cryorolling, which has potential for large-scale industrial production of nanostructured materials; (2) Four-layer accumulative roll bonding, which has potential to produce nanostructured materials at room temperature with high bonding quality, used for fabrication of ultrafine material sheets; (3) Asymmetric Rolling of accumulative roll bonding-processed sheets, which has potential for large-scale industrial production of nanocomposite foils.

VO2/Si–Al gel nanocomposite thermochromic smart foils: Largely enhanced luminous transmittance and solar modulation

VO2 nanoparticles with a dimension of approximately 20nm were obtained by simple mechanical bead-milling method, which were well dispersed in transparent silica–alumina (Si–Al) gel matrix to form nanocomposites. The VO2/Si–Al gel thermochromic nanocomposite foils were fabricated with various VO2 solid contents and foil thickness. With 10% VO2 loading and 3μm foil thickness, high luminous transmittance (Tlum(20°C)=63.7% and Tlum(90°C)=54.4%), and large solar modulation ability (ΔTsol=12%) can be obtained which surpasses the best reported results (nanoporous films:Tlum(20°C)=43.3%, Tlum(90°C)=39.9% and ΔTsol=14.1%). This current approach provided a simple and scalable preparation method with the best combined thermochromic performance.

Bioactivity of Fibrous Polymer Based Nanocomposites for Application in Regenerative Medicine

Aim of the work was production of nanocomposite polymer fibres containing ceramic particles using the electrospinning method and characterisation of morphology and bioactivity of the produced materials. The first stage of investigations consisted in preparation of a series of poly-L-lactide (PLA) solutions in various solvents mixtures in order to reach viscosity which would allow formation of fibres by the electrospinning method. Ceramic nanoparticles such as tricalcium phosphate (TCP) and silica (SiO2) were used as nanofillers of the polymer matrix. Their particle size distribution in the solvent solution as well as in the polymer suspension was determined by dynamic light scattering method (DLS). Morphology of the nanoparticles was observed using transmission electron microscopy (TEM). Distribution of the nanofillers in the nanocomposite fibres as well as diameter and morphology of the fibres was assessed using scanning electron microscopy with energy dispersive spectroscopy method (SEM/EDS). Effect of the nanofillers addition and the shaping method on the structure of the PLA matrix was investigated on the basis of the thermal analysis methods (TG/DSC) on the nanocomposite foils prepared by casting. It was revealed that the nanocomposite fibres showed apatite nucleation in in vitro conditions i.e. after incubation in SBF (37°C/ 3 days).