Nanocomposite Solution Research Articles

Knittle Pressure Sensor Based on Graphene/Polyvinylidene Fluoride Nanocomposite Coated on Polyester Fabric.

In this paper, a knittle pressure sensor was designed and fabricated by coating graphene/Polyvinylidene Fluoride nanocomposite on the knitted polyester substrate. The coating was carried out by a dip-coating method in a nanocomposite solution. The microstructure, surface properties and electrical properties of coated layers were investigated. The sensors were tested under the application of different pressures, and the corresponding sensor signals were analyzed in terms of resistance change. It was observed that the change in resistance was 55% kPa-1 with a sensitivity limit of 0.25 kPa. The sensor model was created and simulated using COMSOL Multiphysics software, and the model data were favorably compared with the experimental results. This investigation suggests that graphene-based nanocomposites can be used in knittle pressure sensor applications.

Green Synthetic Approaches of 2-Hydrazonothiazol-4(5H)-ones Using Sustainable Barium Oxide-Chitosan Nanocomposite Catalyst.

The diverse applications of metal oxide-biopolymer matrix as a nanocomposite heterogenous catalyst have caused many researches to scrutinize the potential of this framework. In this study, a novel hybrid barium oxide-chitosan nanocomposite was synthesized through a facile and cost-effective co-precipitation method by doping barium oxide nanoparticles within the chitosan matrix at a weight percentage of 20 wt.% BaO-chitosan. A thin film of the novel hybrid material was produced by casting the nanocomposite solution in a petri dish. Several instrumental methods, including Fourier-transform infrared (FTIR), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD), were used to analyze and characterize the structure of the BaO-CS nanocomposite. The chemical interaction with barium oxide molecules resulted in a noticeable displacement of the most significant chitosan-specific peaks in the FTIR spectra. When the surface morphology of SEM graphs was analyzed, a dramatic morphological change in the chitosan surface was also discovered; this morphological change can be attributed to the surface adsorption of BaO molecules. Additionally, the patterns of the XRD demonstrated that the crystallinity of the material, chitosan, appears to be enhanced upon interaction with barium oxide molecules with the active sites, OH and NH2 groups, along the chitosan backbone. The prepared BaO-CS nanocomposite can be used successfully as an effective heterogenous recyclable catalyst for the reaction of N,N'-(alkane-diyl)bis(2-chloroacetamide) with 2-(arylidinehydrazine)-1-carbothioamide as a novel synthetic approach to prepare 2-hydrazonothiazol-4(5H)-ones. This new method provides a number of benefits, including quick and permissive reaction conditions, better reaction yields, and sustainable catalysts for multiple uses.

The Role of Period Modulation on the Structure, Composition and Mechanical Properties of Nanocomposite Multilayer TiAlSiN/AlSiN Coatings

This paper presents the results of the investigation of a multilayer TiAlSiN/AlSiN coating. A novel coating architecture with a period consisting of nanocomposite sublayers of TiAlSiN and AlSiN was developed. We discovered that the combination of a harder sublayer with a more elastic one allows for obtaining a suitable combination of superhardness and enhanced toughness. The coating was deposited by cathodic arc technology. The EDS, XRD, and XRS analyses revealed that the nanocomposite structure is composed of TiAlSiN and AlSiN nanocrystallites, with sizes of 12–13 nm and 4–5 nm, respectively. The nanograin phase is incorporated in an amorphous Si3N4 matrix. The achieved structure causes the presence of four factors contributing to the hardness increase: nanocomposition, solid solution, refinement hardening, and the formation of many interfaces. An instrumented indentation test was used to investigate the mechanical properties. The developed coating possesses a superhardness of 49.5 GPa and a low elastic modulus of 430 GPa, resulting in an improved elastic strain resistance of 0.11, a plastic deformation resistance of 0.58 GPa, and an elastic recovery of 68%. These results imply that the developed coating combines high stability with mechanical degradation under external influence and provides an improved ability to absorb energy at deformation before fracture, and high elastic recovery. The investigation of the effect of the period modulation on the structure, composition, and mechanical properties of the nanocomposite multilayer TiAlSiN/AlSiN coating showed that the superhardness was due to the nanocomposite and solid solution hardening rather than the increased number of interfaces. The demonstrated combination of superhardness with high elasticity and improved toughness determines the developed nanocomposite TiAlSiN/AlSiN coating as very suitable for industrial applications such as high speed and dry machining.

High-k Solution-Processed Barium Titanate/Polysiloxane Nanocomposite for Low-Temperature Ferroelectric Thin-Film Transistors.

Ferroelectric nanoparticles have attracted much attention for numerous electronic applications owing to their nanoscale structure and size-dependent behavior. Barium titanate (BTO) nanoparticles with two different sizes (20 and 100 nm) were synthesized and mixed with a polysiloxane (PSX) polymer forming a nanocomposite solution for high-k nanodielectric films. Transition from the ferroelectric to paraelectric phase of BTO with different nanoparticle dimensions was evaluated through variable-temperature X-ray diffraction measurement accompanied by electrical analysis using capacitor structures. A symmetric single 200 peak was constantly detected at different measurement temperatures for the 20 nm BTO sample, marking a stable cubic crystal structure. 100 nm BTO on the other hand shows splitting of 200/002 peaks correlating to a tetragonal crystal form which further merged, thus forming a single 200 peak at higher temperatures. Smaller BTO dimension exhibits clockwise hysteresis in capacitance-voltage measurement and correlates to a cubic crystal structure which possesses paraelectric properties. Bigger BTO dimension in contrast, demonstrates counterclockwise hysteresis owing to their tetragonal crystal form. Through further Rietveld refinement analysis, we found that the tetragonality (c/a) of 100 nm BTO decreases at a higher temperature which narrows the hysteresis window. A wider hysteresis window was observed when utilizing 100 nm BTO compared to 20 nm BTO even at a lower loading ratio. The present findings imply different hysteresis mechanisms for BTO nanoparticles with varying dimensions which is crucial in understanding the role of how the BTO size tunes the crystal structures for integration in thin-film transistor devices.

Influence of α-Fe2O3, CuO and GO 2D nano-fillers on the structure, physical properties and antifungal activity of Na-CMC–PAAm blend

The present work aims to improve the uses of the carboxymethyl cellulose–polyacrylamide (Na-CMC–PAAm) blend for energy storage, optoelectronic applications, biological control, and plant disease management. Nano-sized materials (α-Fe2O3 nanoplates (NP), CuO NP, and GO nanosheets (NS), were synthesized and incorporated into the blend. The phase purity and morphologies of the used fillers were studied by XRD and HR-TEM. The interactions and complexation between the nano-fillers and the blend chains were investigated using XRD and FTIR spectra. The chemical composition and surface morphology of the nanocomposites were studied using EDS and FE-SEM analysis. UV-vis-NIR spectra revealed that the blend shows about 95% transmittance, reduced by 10–30% after doping. The absorption and refractive indices, as well as the optical gaps of the blend, were greatly affected by the doping. The dielectric constant and loss depend on the type of filler and the applied frequency. The maximum ac conductivity of the blend at 303 K and 4.0 MHz is 21.5 × 10–4 S/m and increased to 23.5 × 10–4 S/m after doping with CuO NP. The thermal stability, activation energy, stress–strain curves, and tensile strength are dependent on the filler type. All nanocomposite solutions except the blend exhibited a wide range of antifungal properties against pre- and post-harvest phytopathogenic fungi. Aspergillus niger among the examined fungi showed high sensitivity to the tested nanocomposite solutions. Furthermore, the CuO/blend nanocomposite had the highest antifungal activity against all tested fungi. Based on that, we suggest the use of CuO/blend and GO/blend nanocomposites to control and combat pre- and post-harvest fungal plant diseases.

M3+/NaTiO3/PVA–chitosan nanocomposites (M = Ga, Ce, Nd or Er): novel solid polymer electrolytes for supercapacitors

Designing flexible and thermally stable solid polymer-electrolyte (SPE) -based green materials for energy storage devices is an interesting approach from environmental and technological points of view. In this paper, NaTiO3 (ST) nanofibers of diameters in the range of 4.88–9.48 nm were hydrothermally prepared and loaded into the poly(vinyl alcohol)–chitosan (PVA–Ch) bio-blend via solution casting. Additionally, the obtained nanocomposite solution was mixed with Ga3+ and rare Earths (Ce3+, Nd3+, or Er3+) for preparing novel solid polymer electrolyte films. XRD results indicated the semicrystalline nature of all samples, and the degree of crystallinity decreased after loading these additives. FE-SEM and EDS were used to investigate the surface morphology, fracture cross-section and the elemental chemical composition. FTIR analysis confirmed the complexation and complete dissociation of the salts inside the blend. UV–vis spectroscopy showed that the optical band gap of the films was reduced from 4.4 eV to 3.5 eV, and the refractive index is in the range of 2.376–2.648. The thermo-gravimetric analysis (TGA) revealed that the samples are thermally stable until 200 °C, and the maximum decomposition occurs in the temperature range 255–300 °C. In addition, four endothermic peaks were detected in the differential scanning calorimetry thermograms. Dielectric properties were measured in the fRequency range of 100 Hz–8.0 MHz and at temperatures in the range of 30–120 °C. The dielectric constant and ac conductivity were greatly improved due to doping with ST and mixing the salts. The small dielectric loss associated with the improvements in the dielectric constant and ac conductivity suggest the use of the ST/blend and salts/ST/blend films for energy storage devices and related applications.

Sol-Gel growth of zinc oxide particles on graphene sheets for mode-locking in Thulium/Holmium-doped fiber laser

This work used Graphene/Zinc Oxide (G/ZnO) nanocomposite to generate mode-locked pulses in Thulium/Holmium-doped fiber (THDF). The sol-gel method was used to synthesize the ZnO particles decorated graphene sheets. The G/ZnO nanocomposite solution was deposited onto the arc-shaped fiber that had been fabricated to act as the saturable absorber (SA) device. The nonlinear optical response of G/ZnO-based SA was investigated via the twin detection approach, in which it exhibits a modulation depth of 14.11% and a saturation intensity of 4.23 MW cm−2. After incorporating the fabricated SA into the THDF laser cavity, mode-locked pulses were produced at a threshold pump power of 274.3 mW with a center wavelength of 1895.11 nm, fundamental frequency of 11.82 MHz, and a pulse duration of 1.7 ps. The maximum average output power and single pulse energy were determined to be 1.39 mW and 117 pJ, respectively. The mode-locked pulses generated were exceptionally stable, giving a signal-to-noise ratio (SNR) of 58.2 dB. According to the findings of the current research, it is anticipated that the G/ZnO-arc-shaped fiber-based SA has the potential to produce stable mode-locked lasers in the 2.0 μm region.

Room temperature NH3 gas sensor based on PMMA/RGO/ZnO nanocomposite films fabricated by in-situ solution polymerization

Effective detection of ammonia gas is of great importance due to its detrimental effects on human health, environment, and ecosystem. High-performance composite gas sensors are vital in accomplishing this goal. Herein, we investigate the performance of an ammonia (NH3) gas sensor fabricated via dip-coating the silver interdigitated electrode for PMMA/RGO/ZnO (PRZ) nanocomposite solution with acetone as a solvent. The PRZ ternary nanocomposite was synthesized using the in-situ solution polymerization method and the resistive properties of the films assembled on the interdigitated electrode were analyzed, with respect to the fixed and varying ammonia gas concentrations, using LCR meter. When the sensor is operated in the controlled chamber containing ammonia gas at room temperature, the sensor responds rapidly to ammonia with a fast recovery of 13.02 s at a gas concentration of 350 ppm. The PRZ sensor exhibits high sensing percentage response (527%), excellent repeatability (four times), high sensitivity at low concentrations (less than 10 ppm), swift response and recovery times (1.94 s/13.02 s), and long-term stability (up to 90 days) with fluctuation of 3.2%, which signifies PRZ composite as a potential material for ammonia gas sensor. Aspects such as simplicity of the synthesis process and fabrication, excellent sensing performance, as well as fast response-recovery time at a particular gas concentration are noteworthy in this study. These features can be utilized for the detection of ammonia gas in chemical and biological fields.

In vitro and in situ caries-preventive effect of a new combined fluoride and calcium experimental nanocomposite solution.

To assess the in vitro and in situ effect of experimental combined fluoride and calcium nanocomposite solutions on dental caries prevention. Nanocompound mesoporous silica (MS) with calcium (Ca) and sodium fluoride (NaF) - (MSCaNaF); MS with NaF (MSNaF), NaF solution (positive control), and deionized water (negative control - CG) were studied. The specimens (n=130) were submitted in vitro to a multispecies biofilm in the presence of 2% sucrose. After 24 h and 48 h, the culture medium pH, the percent of surface mineral loss (%SML), and lesion depth (ΔZ) were analyzed. In the in situ study, 10 volunteers participated in four phases of 7-days each. The products were applied on the specimens (n=240) before 20% sucrose solution drips. The polysaccharides (SEPS and IEPS), %SML and roughness (Sa) were evaluated. There was an in vitro decrease in pH values in 24h and 48h, compared to baseline. The MSCaNaF and MSNaF groups obtained lower values of %SML and ΔZ (p < 0.05) than CG and NaF after 24h and were similar to NaF after 48h (p<0.05). In situ results showed similar SEPS and IEPS among all groups after 48h. An after 7-days, the nanocomposites had similar values (p>0.05), while NaF was similar to CG (p>0.05). After 48h, the MSCaNaF and MSNaF reduced the %SML (p<0.05). After 7-days, both experimental nanocomposites were similar to NaF (p>0.05). Regarding Sa, MSCaNaF was better than NaF for both periods (p<0.05). The nanocomposites controlled the in vitro and in situ enamel demineralization, mainly in the initial periods.

Electrosynthesis of silver metallonanocomposites in the 1-vinyl-1.2.4-triazole copolymer matrix with methacrylic acid

Silver nanocomposites were synthesized by the electrochemical method in the matrix of a copolymer of 1-vinyl-1,2,4-triazole with methacrylic acid, by combining the process of electrochemical polymerization with cathodic precipitation of metals on metal electrodes. In the electronic spectra of nanocomposites, absorption bands appear with a maximum in the region of 417–421 nm, which is typical for systems with zero valence silver. The IR spectra show that the polymer structure hardly changes during the formation of nanocomposites and films. The presence of silver in the amorphous polymer phase is indicated by the results of X-ray diffraction studies. The silver content in nanocomposites is 0–9%, which leads to an increase in the viscosity of nanocomposite solutions compared to solutions of the initial copolymers. Transmission electron microscopy data show that the synthesized nanocomposites consist of particles with a diameter of 1–12 nm, predominantly spherical.

Electrospun biodegradable scaffolds based on poly (ε-caprolactone)/gelatin containing titanium dioxide for bone tissue engineering application; in vitro study

In this study, Poly (ε-caprolactone) (PCL)/Gelatin/TiO2 nanofibrous scaffolds were prepared using electrospinning. The effects of TiO2 nanoparticles (NPs) addition on morphology, mechanical, chemical, thermal, and cellular behavior, and antibacterial properties of PCL/gelatin scaffolds were investigated. Different amounts of TiO2 NPs (0.06, 0.6, and 1 w/v %) were incorporated into the polymer blend to form a homogenous nanocomposite solution. The experimental results exhibited that the hydrophilicity of the scaffolds was improved by incorporating TiO2 NPs, as shown by the water contact angle measurement. Also, the mechanical and thermal behaviors of fabricated scaffolds were enhanced. Moreover, Human bone marrow-derived mesenchymal stem cells (hMSC) were used to investigate the bioactivity and biocompatibility of scaffolds. The MTT assay results showed no toxicity effect for scaffolds. However, releasing reactive oxygen at the highest concentration of TiO2 was remarkably increased, resulting in cell toxicity. Hybridizing biopolymer with TiO2 nanoparticles improves its bone regeneration capability. Thereby, incorporating an optimum amount of TiO2 NPs into PCL/Gelatin composites could be a promising approach for bone tissue engineering applications.

PET/Graphene Nanocomposite Fibers Obtained by Dry-Jet Wet-Spinning for Conductive Textiles.

The combination of polyethylene terephthalate (PET), one of the most used polymers in the textile industry, with graphene, one of the most outstanding conductive materials in recent years, represents a promising strategy for the preparation of conductive textiles. This study focuses on the preparation of mechanically stable and conductive polymer textiles and describes the preparation of PET/graphene fibers by the dry-jet wet-spinning method from nanocomposite solutions in trifluoroacetic acid. Nanoindentation results show that the addition of a small amount of graphene (2 wt.%) to the glassy PET fibers produces a significant modulus and hardness enhancement (≈10%) that can be partly attributed to the intrinsic mechanical properties of graphene but also to the promotion of crystallinity. Higher graphene loadings up to 5 wt.% are found to produce additional mechanical improvements up to ≈20% that can be merely attributed to the superior properties of the filler. Moreover, the nanocomposite fibers display an electrical conductivity percolation threshold over 2 wt.% approaching ≈0.2 S/cm for the largest graphene loading. Finally, bending tests on the nanocomposite fibers show that the good electrical conductivity can be preserved under cyclic mechanical loading.

New Nanometal-Containing Hepatoprotectors: Obtaining and Studying Biological Properties

Abstract The article is devoted to the study of the biological properties of nanocomposites obtained by immobilisation of precious metals (Au2+, Ag2+) in the structures of extracts of plant hepatoprotectors (milk thistle, saffron), in experiments on small sexually mature laboratory animals. Aqueous solutions of nanocomposites were administered to animals intraperitoneally 30 minutes prior to exposure to ionising radiation. Quantitative changes in lipid peroxidation were determined on the basis of the analysis of the concentration of malonic dealdehyde and hydroperoxide in liver tissue of control and experimental animals. It was revealed that nanocomposites introduced to animals before irradiation partially protect them from its destructive effect. More pronounced hepatoprotective effects in comparison with Ag2+ ions are manifested by Au2+ ions. Animals were also tested for behavioural responses in an open field model against the background of the introduction of a corresponding dose of the nanocomposite solution before irradiation. There were also changes in behavioural responses.

A Chemiresistor Sensor Array Based on Graphene Nanostructures: From the Detection of Ammonia and Possible Interfering VOCs to Chemometric Analysis.

Sensor arrays are currently attracting the interest of researchers due to their potential of overcoming the limitations of single sensors regarding selectivity, required by specific applications. Among the materials used to develop sensor arrays, graphene has not been so far extensively exploited, despite its remarkable sensing capability. Here we present the development of a graphene-based sensor array prepared by dropcasting nanostructure and nanocomposite graphene solution on interdigitated substrates, with the aim to investigate the capability of the array to discriminate several gases related to specific applications, including environmental monitoring, food quality tracking, and breathomics. This goal is achieved in two steps: at first the sensing properties of the array have been assessed through ammonia exposures, drawing the calibration curves, estimating the limit of detection, which has been found in the ppb range for all sensors, and investigating stability and sensitivity; then, after performing exposures to acetone, ethanol, 2-propanol, sodium hypochlorite, and water vapour, chemometric tools have been exploited to investigate the discrimination capability of the array, including principal component analysis (PCA), linear discriminant analysis (LDA), and Mahalanobis distance. PCA shows that the array was able to discriminate all the tested gases with an explained variance around 95%, while with an LDA approach the array can be trained to accurately recognize unknown gas contribution, with an accuracy higher than 94%.

Honey-mediated synthesis of Cr2O3 nanoparticles and their potent anti-bacterial, anti-oxidant and anti-inflammatory activities

Green synthesis of nanoparticles has gained tremendous attention in recent era which is pertinent to their unique properties and broad applications. This approach is cost-effective, environment-friendly as well as highly biocompatible. In this research, chromium oxide nanoparticles (Cr2O3-NPs) were synthesized by using Apis mellifera honey as a reducing and capping agent and their anti-bacterial, anti-biofilm, anti-oxidant and anti-inflammatory abilities were explored. Ultra Violet-visible double beam spectroscopy revealed that chromium underwent d-d transition during synthesis of nanoparticles. X-ray diffraction (XRD) analysis verified that Cr2O3-NPs were crystalline in nature and average crystal size was 24 nm. Energy-dispersive X-ray (EDX) analysis confirmed that chromium and oxygen formed nano-composites in solution which possessed a stable form. Scanning electron microscopy (SEM) provided morphological characteristics of nanoparticles and proved that their average size was 20 nm. Cr2O3-NPs displayed excellent anti-bacterial activity (minimum inhibition zone, 20 mm; maximum inhibition zone, 26 mm) against 30 selected clinical isolates of Klebsiella pneumoniae as determined by agar well-diffusion method. Their antibacterial activity was considerably superior to that of three selected antibiotics including Gentamicin, Ciprofloxacin and Cefepime. However, no synergism was observed between nanoparticles and these antibiotics as calculated from fractional inhibitory concentration index (FICI) values all of which were > 1. The synthesized nanoparticles possessed good biofilm inhibition potential (60 % to 73 %) at all concentrations (20 µg/ml to 50 µg/ml) tested. Cr2O3-NPs exhibited excellent anti-oxidant activity (IC50 = 128 µg/ml) which was nearly equivalent to that of ascorbic acid. Anti-inflammatory effect of Cr2O3-NPs was also significant (IC50 = 549 µg/ml) and comparable to that of standard. Both anti-oxidant and anti-inflammatory capacities were found to increase with an increase in the concentration of Cr2O3-NPs. In conclusion, this work revealed that Apis mellifera honey-mediated synthesis of Cr2O3-NPs could be investigated for future biomedical applications.

Dielectric characterization of P(VDF-TrFE)-CuO nanocomposite solutions in the microwave frequency range using open-ended coaxial probe technique

In this study, we measured the dielectric permittivity of P(VDF-TrFE)-CuO nanocomposite solutions in the microwave frequency range using an open-ended coaxial probe technique at room temperature. The dielectric permittivity, complex dielectric permittivity ε*= ε'-j ε'' and dielectric loss are determined for the composite solutions by the impedance measurements. It is observed that as the concentration of CuO increases up to 10 wt% in P(VDF-TrFE), dielectric permittivity is decreased. Upon further increase in the concentration of CuO an increase in ε' is noticed. The dielectric relaxation time of these composite solutions is analysed from the Havriliak-Negami relation. From the Cole-Cole plot, the optical dielectric constant, static dielectric constant, shape factor α, and molecular relaxation times are calculated. This study gives an insight into the relaxation behaviour of P(VDF-TrFE)-CuO nanocomposite solutions in the microwave frequency region (0.02 < GHz < 50).

Improving the optical, dielectric properties and antimicrobial activity of Chitosan–PEO by GO/MWCNTs: Nanocomposites for energy storage and food packaging applications

This work is an attempt to improve the multifunctionality of chitosan–polyethylene oxide (Ch.–PEO) blend for different industrial applications including energy storage and food packaging applications. Graphene oxide (GO)/blend and multi-walled carbon nanotubes (MWCNTs)/GO/blend films were prepared by the solution casting method. FTIR analysis indicated the existence of Ch. and PEO functional groups and the positive interaction between the added nanofillers and the blend chains. XRD data confirmed interfacial compatibility between PEO and Ch. and showed that the semicrystalline nature of the blend was decreased after the incorporation of the filler. SEM analysis displayed that the blend surface is homogenous and crack-free, and the MWCNTs/GO were well-dispersed and uniformly distributed on the surface. The blend showed transmittance in the visible and NIR regions in the range of 76–91%. Loading MWCNTs/GO reduced this range and significantly increased the extinction coefficient of the blend. The indirect/direct band gap decreased from 4.3/5.2 eV to 3.0/3.8 eV with increasing fillers content. Moreover, the optical constants of the blend and nanocomposite films were determined. The dielectric measurements revealed that MWCNTs/GO doping increases the defects and results in a larger number of dipoles inside the blend and hence increases the dielectric constant of the blend. In addition, tan (δ) for all films is very small (˂ 0.05) and MWCNTs/GO/blend exhibits conductivity four times greater compared with the pure blend. The conduction mechanism, dielectric modulus, and Cole-Cole plots in the temperature range of 30–110 °C and frequencies in the range of 10−2 Hz–10 MHz were reported. The thermal analyses (TGA and DSC) for the blend and nanocomposite films were performed in the temperature range of 25–550 °C. TGA and DTG revealed three distinct weight-loss events for the samples; 25–122 °C, 229–360 °C, and 365–440 °C. The doped samples were more thermally stable where the blend lost 20% of its weight at 180.9 °C, while after doping with GO and codoping with MWCNTs, this temperature increased to 190.5 and 210.2 °C, respectively. The blend and nanocomposite solutions showed a wide antimicrobial activity against gram-positive and gram-negative bacteria, yeast, and fungi. Specifically, both GO/Ch.–PEO and 0.004%MWCNTs/GO/Ch.–PEO represented the highest antimicrobial against all tested microbes. Staphylococcus aureus ATCC 8095 was founded to be the most sensitive among the examined microbes. Additionally, the least sensitivity to studied solutions was recorded by Penicillium roqueforti. The improvements in the optical and dielectric properties make the prepared nanocomposites suitable for energy storage devices, while the antimicrobial activity suggests the use of GO/Ch.–PEO and MWCNTs/GO/Ch.–PEO nanocomposites for food packaging applications.

Synthesis, structural, optical and electrical characterization of Y2O3/poly(ethylene glycol)–poly(vinyl chloride) based nanocomposite solid polymer electrolytes

AbstractNanocomposite solid polymer electrolytes (NCSPEs) have attracted a lot of attention as excellent candidates for future electronics, photonics and energy storage devices. In this work, Y2O3 (YO) nanosheets were prepared by a free‐template sol–gel method and incorporated inside a poly(ethylene glycol)–poly(vinyl chloride) (blend) matrix via solution casting. NCSPE films were then prepared by adding NaClO4 (NC) or LiCl (LC) to the nanocomposite solutions. XRD and field emission SEM showed that YO has a body‐centered cubic structure and a crystallite size of 24.8 nm, and looks like nanosheets with a high purity. The XRD results of the films showed that YO loading and salt complexation increase the films' amorphous structure. SEM was used to study the surface morphology and film thickness. Fourier transform infrared spectra confirmed the complexation and interactions between the YO/blend and NC or LC. UV–visible spectroscopy revealed that the films display low transmittance (˂17%), an extinction coefficient k between 0.2 × 10−3 and 1 × 10−3 and a comparatively high refractive index. The band gap of the blend decreased from 4.3 to 4.0 eV on loading YO, and NC exhibited a higher impact on Eg compared with LC. A significant increase in with complexing was reported and the maximum value was 7.4 × 10−4 S cm−1 for the 10 wt% NC/YO/blend structure. The NCSPE films are ionic conductors and have a non‐Debye type of conductivity relaxation, and the applied AC conduction mechanism is correlated barrier hopping. © 2022 Society of Industrial Chemistry.

Synthesis of green thermo-responsive amphoteric terpolymer functionalized silica nanocomposite derived from waste vegetable oil triglycerides for enhanced oil recovery (EOR)

Despite the high efficiency of polymer flooding as a chemical enhanced oil recovery (CEOR) technique, the low thermal stability and poor salt resistance of widely applied partially hydrolyzed polyacrylamide (HPAM) limited the application of this technique in oil reservoirs at harsh reservoir conditions of high–temperature and high–salinity (HTHS). These inadequacies of HPAM, result in the urge for an environmentally friendly polymer with good viscosifying properties and a substantial effect on mobility ratio at HTHS reservoir conditions. In this research, a high oleic acid waste vegetable oil (WVO) is utilized to synthesize a novel environmentally benign, thermo-responsive amphoteric nanocomposite for EOR applications at HTHS reservoir conditions. A green route transesterification reaction has been utilized to synthesize a novel thermo-sensitive monomer from WVO. The existence of unsaturated fatty acids isolated double bonds and acryloyl functional groups in the synthesized monomer has been confirmed using different characterization methods. The reactive acryloyl double bond in the synthesized monomer has been copolymerized with acrylamide, acrylacyloxyethyltrimethyl ammonium chloride, and 2-acrylamide-2-methylpropane sulfonic acid in presence of dimethylphenylvinylsilane via free radical emulsion polymerization. The synthesized nanocomposite has been characterized by FTIR, 1H NMR, SEM, EDX, TEM, and DLS. The thermal stability of the nanocomposite has been evaluated by TGA and DTA analysis. The results indicated that nanocomposite solution exhibited a pouncing thermo-thickening behaviour and superior viscosifying properties even at an ultra-low polymer concentration of 0.04 wt% as the temperature increased from 25 to 100 °C, with increasing salinity from 10,000 to 230,000 ppm as well as salt-free solutions. Flooding experiments demonstrated that the oil recovery factor reached 15.4 ± 0.1 % using low nanocomposite concentrations of 0.04 wt%, 22.6 ± 0.3 % using nanocomposite concentrations of 0.06 wt% and 25 ± 0.2 % using 0.1 wt% nanocomposite concentrations evaluated under hostile conditions of 100 °C and salinity of about 230,000 ppm. This research offers a new direction for the synthesis of a novel green, high molecular weight thermoresponsive nanocomposite for EOR application at extremely harsh reservoir conditions via WVO valorization.

The formation of silver nanoparticles in solutions of sodium salts of carboxymethyl starch

The possibility of obtaining a biodegradable bactericidal composition containing silver nanoparticles by the reduction of silver ions using sodium carboxymethyl starch and UV irradiation has been investigated in this work. It is shown that the degree increase of substitution of carboxymethyl groups in NaCMS leads to an intensity increase of absorption of the surface plasma resonance bands of AgNP and an intensification of the Ag+ reduction process to Ag0. The intensity of the emerging Ag peak shows a complete reduction of Ag+ to Ag0 and the effectiveness of CMS in stabilizing the resulting AgNP. The results obtained from the EDX spectrum, together with the results of the SEM images, are strong evidence for the formation of AgNP nanoparticles and indicate the long-term colloidal stability of the product. It is shown that the processed nanocomposite solution AgCMS hosiery and non-woven materials have high antibacterial activity.