Oxide Nanocomposite Films Research Articles

Melt-stretched poly(vinylidene fluoride)/zinc oxide nanocomposite films with enhanced piezoelectricity by stress concentrations in piezoelectric domains for wearable electronics

Till date, fabrication of polymeric-inorganic piezoelectric nanocomposites with enhanced piezoelectricity is considered a potential solution for future high-performance flexible sensing devices. Herein, we report the preparation of poly(vinylidene fluoride)/zinc oxide (PVDF/ZnO) piezoelectric nanocomposite films via a combined approach of adding nanofillers, irradiation crosslinking and melt stretching. The melt-stretched film contains closely aligned β-phase nanofibrils with a high content (>90 % of the crystalline phase) serving as piezoelectric domains. Meanwhile, the incorporation of ZnO nanoparticles creates stress concentrations, promoting the piezoelectric response of β-nanofibrils and also the stress-induced polarization under loading. As a result, the film displays not only a superior mechanical strength (>100 MPa), but also largely enhanced piezoelectric output performance after poling, including wide response range, high sensibility to weak force and excellent working durability (>10,000 cycles). The optimal film with ZnO content of 5 wt% has a pressure sensitivity of ∼ 1.7 V/kPa under 0–1 kPa, almost twice that (∼0.8 V/kPa) of the pure PVDF without nanofillers. With the outstanding piezoelectric properties, potential applications of film as a flexible wearable sensor in monitoring human motions and subtle physiological signals are demonstrated. The results provide a new melt processing strategy that is easily scalable for developing high-performance PVDF-based piezoelectric nanocomposite films towards wearable electronics.

Boosting solar fuel production of bismuth ferrite thin film by incorporating reduced graphene oxide

In this study, a facile chemical approach was utilized to successfully fabricate a porous bismuth ferrite (BiFeO3, BFO)/reduced graphene oxide (rGO) nanocomposite thin film as a photoanode for photoelectrochemical (PEC) water splitting. The BFO nanoparticles possess a pure rhombohedral distorted perovskite crystal structure and are grafted onto rGO nanosheets. BFO/rGO (BGO) thin film has smaller nanoparticles (around 100 nm) and higher porosity which provides a higher surface area compared to BFO. Moreover, BGO exhibits higher visible absorption, a narrower band gap energy of 1.95 eV, and a lower recombination rate of charge carriers. The BGO photoanode has a maximum photocurrent density of 0.451 mA.cm−2 at 1.23 V versus the reversible hydrogen electrode (RHE) under 100 mW.cm−2 illumination which is 2.5 times more than the BFO photoanode. The applied bias photon-to-current efficiency (ABPE) of BGO nanocomposite film is 0.21%, which is approximately 2.5 times that of BFO. The obtained results reveal an intimate heterostructure between BFO nanoparticles and rGO nanosheets. The charge separation and transfer of BFO are significantly boosted by incorporating the rGO. This study sheds light on the mechanism insights of enhanced PEC water splitting in BFO/rGO thin film, offering a new approach to the design and fabrication of high-efficiency photoanodes.

Synthesis and Characterization of Chitosan-Containing ZnS/ZrO2/Graphene Oxide Nanocomposites and Their Application in Wound Dressing

The development of scaffold-based nanofilms for the acceleration of wound healing and for maintaining the high level of the healthcare system is still a challenge. The use of naturally sourced polymers as binders to deliver nanoparticles to sites of injury has been highly suggested. To this end, chitosan (CS) was embedded with different nanoparticles and examined for its potential usage in wound dressing. In detail, chitosan (CS)-containing zinc sulfide (ZnS)/zirconium dioxide (ZrO2)/graphene oxide (GO) nanocomposite films were successfully fabricated with the aim of achieving promising biological behavior in the wound healing process. Morphological examination by SEM showed the formation of porous films with a good scattering of ZnS and ZrO2 nanograins, especially amongst ZnS/ZrO2/GO@CS film. In addition, ZnS/ZrO2/GO@CS displayed the lowest contact angle of 67.1 ± 0.9°. Optically, the absorption edge records 2.35 eV for pure chitosan, while it declines to 1.8:1.9 scope with the addition of ZnS, ZrO2, and GO. Normal lung cell (WI-38) proliferation inspection demonstrated that the usage of 2.4 µg/mL ZnS/ZrO2/GO@CS led to a cell viability % of 142.79%, while the usage of 5000 µg/ mL led to a viability of 113.82%. However, the fibroblast malignant cell line exposed to 2.4 µg/mL ZnS/ZrO2/GO@CS showed a viability % of 92.81%, while this percentage showed a steep decline with the usage of 5000 µg/ mL and 2500 µg/mL, reaching 23.28% and 27.81%, respectively. Further biological assessment should be executed with a three-dimensional film scaffold by choosing surrounding media characteristics (normal/malignant) that enhance the selectivity potential. The fabricated scaffolds show promising selective performance, biologically.

A novel photoelectrochemical sensor based on flower-like SnS2, sea urchin-like AgBiS2 and graphene oxide nanocomposite film for efficient and sensitive detection of acetaminophen in lake water samples

As an emerging detection technology, photoelectrochemical sensors have been widely noticed for their unique technical features. Among others, the technology has been widely used in the fields of drug, biological antibody or antigen and contaminant detection. Secondly, acetaminophen, as a novel environmental pollutant, is difficult to be degraded in the ecosystem, which in turn causes serious impacts on the ecosystem. Therefore, in this work, we designed a photoelectrochemical sensor based on a composite film of flower-like SnS2, sea urchin-like AgBiS2 and graphene oxide for the detection of acetaminophen in water samples. Among them, graphene oxide, as a two-dimensional carbon-based material, can immobilize other photoelectric materials well. In addition, the flower-like SnS2 and sea urchin-like AgBiS2 can enhance the intensity of the photoelectric response due to their synergistic effect. Notably, the combination of graphene oxide with SnS2 and AgBiS2 revealed an exponential increase in the photoresponse intensity, indicating that SnS2/AgBiS2/GO has a satisfactory photoresponse intensity. At the same time, the photoelectrochemical sensor exhibited sensitive detection performance (LOD = 4 nM) and a wide detection range (0.01–50 μM) for acetaminophen under optimal detection conditions. Moreover, it also showed excellent detection performance in the detection of actual water samples, indicating that it can be applied to the detection of acetaminophen in lakes.

Antibacterial poly(butylene succinate-co-terephthalate)/titanium dioxide/copper oxide nanocomposites films for food packaging applications

Titanium dioxide (TiO2)/copper oxide (CuO) nanoparticles (NPs) were synthesized by co-precipitation method. The photocatalytic activities of TiO2 were enhanced by the incorporation of CuO. The poly(butylene succinate-co-terephthalate) (PBST)-based nanocomposite (PTC) films were prepared via solvent casting method. Mechanical properties, UV-Vis light barrier, water vapor permeability (WVP), antibacterial properties, and preservation properties of composite films were evaluated. When the content of TiO2/CuO NPs was 3 %, the best overall properties of the film were obtained. The tensile strength and elongation at break reached maximum values of 35.6 ± 0.4 MPa and 590.7 ± 5.3 %, respectively. Meanwhile, the WVP values and UV-Vis transmittance of PTC-3 film decreased. The inhibition rates were close to 90 % against Staphylococcus aureus and Escherichia coli. Moreover, the PTC-3 film could extend the shelf life of cherry tomato after conducting preservation experiments for 18 days. Prepared PTC films had potential for food packaging.

Enhancing selectivity of solar absorber using reduced graphene oxide modified nickel oxide nanocomposite thin films

Commercial solar selective absorbers prepared through several techniques have encountered drawbacks of necessitating complicated and expensive equipment, substantial materials requirement, and polluting environment. In this context, carbon incorporated metal oxide thin films have shown promise of low-cost, non-toxic, and efficient solar selective absorbers. In particular, association of reduced graphene oxide (rGO) and nickel oxide (NiO) could facilitate highly ascertained optical properties, environment friendliness, and low-cost. Present study focuses on preparing a novel, high performance, and low-cost rGO-NiO solar selective absorber thin films. Thin films comprised of reduced graphene oxide modified nickel oxide nanocomposites (rGO-NiO NCs) were prepared through solvothermal route and coated on aluminum (Al) substrates by dip-coating technique. The rGO-NiO NCs examined using X-ray diffractometer revealed formation of face centered cubic crystallite structure. The scanning electron microscope images disclosed spherical morphology of NiO decorated on the rGO sheets. The spectra derived from energy-dispersive X-ray spectroscopy ascertained absence of peaks corresponding to impurities. The Raman investigation exhibited high intensity ratio (0.97) of the rGO-NiO NCs that described higher disorder and binding sites. The optical property analysis of the rGO-NiO NC (0.2 wt% rGO) thin film performed in UV–vis-NIR reflectance spectroscopy showed high absorptance (α = 88.03 %) and low thermal emittance (ε = 4.5 %), which eventually delivered high solar selectivity (ξ) of 19.56. These findings suggest that the prepared 0.2 % rGO-NiO NC thin film can be utilized as an appropriate selective absorber for solar to thermal energy conversion.

Furanoate Polyesters/Polylactide/Reduced Graphene Oxide Nanocomposite Films: Thermomechanical and Gas Permeation Properties

AbstractThis work aims at preparing bioderived polymer films by blending poly(lactic) acid (PLA) and poly(dodecylene 2,5‐furandicarboxylate) (PDoF) and containing reduced graphene oxide (rGO) as a multifunctional filler in variable weight fraction (from 0.25 to 2 phr). Although the PLA/PDoF blend results as immiscible, the addition of rGO leads to smaller (from 2.6 to 1.6 µm) and more irregularly shaped PDoF domains and to a better PLA/PDoF interfacial adhesion, which suggests that rGO may act as a blend compatibilizer. Dynamic mechanical thermal analysis (DMTA) shows that rGO shifts the glass transition of PDoF (≈5°C) to higher temperatures. The addition of 10 wt% PDoF in PLA increases the strain at break (+145%), and the addition of 0.25 phr of rGO to this blend increases its tensile strength (+13%), without significantly modifying the strain at break. Finally, rGO strongly decreases the diffusivity and permeability to O2, N2, and CO2 due to an increased diffusion path for gas molecules. These results highlight the positive and sometimes synergistic role of PDoF and rGO in tuning the thermomechanical and gas permeation properties of PLA.

High‐lignin‐content rice straw cellulose nanofibers/graphene oxide nanocomposites films: Electrical and mechanical properties

AbstractRice straw nanofibers (RSNF) with high lignin content were used in making nanocomposites with graphene oxide (GO) at loading ratios from 0.625% to 5% (based on weight of RSNF). The prepared RSNF/GO films were characterized regarding their tensile strength, equilibrium moisture content (EMC), and electrical properties. Microstructure of the films was examined using scanning electron microscopy (SEM). Addition of 2.5% of GO resulted in increasing tensile strength and Young's modulus by 33.5% and 21.5%, respectively. Presence of GO significantly reduced moisture sorption of the films. Electrical conductivity measurement showed significant increase in permittivity (ε′) upon increasing GO loading. The ionic conductivity value of films containing 5% of GO was 10−7 S cm−1, which is acceptable value for use as antistatic and/or dissipated films. The electrical properties of the prepared low‐cost high‐lignin‐content RSNF/GO films could have potential use in flexible electronic applications such as in energy harvesting and storage.

Effect of chalcone moiety on AC conductance of Metal Oxide Nano Composite doped thin polymer film

ABSTRACT PVA, Chitosan, transition metal oxide nanocomposites, and a chlorinated chalcone moiety were used to create a 0.03 cm−1 thin polymer film. Prepared films were characterized using available techniques. The prepared film shows a semi-crystalline nature, proved by XRD analysis, and the nano-scale crystalline size (40–150 nm) was also observed. The surface of the film was smooth and a blooming flower resembling structure appeared in the SEM images obtained at 5 µm. The XPS and EDX spectra reveal the presence of added transition metals and other elements present in the prepared polymer thin film. The prepared film undergoes multistage decomposition upon heating, which was proved by TGA analysis. FT-IR analysis of the film shows that there was no chemical interaction between the added compound and the host polymer; instead, physical interactions alone persisted. Higher AC conductivity was observed with a value of 1.30 × 10−6 Scm−1 at room temperature for polymer composite film made up of MONC and DCHP. This conductance varies with temperature, and at higher temperatures, both dielectric loss and dielectric constant are high. It was discovered that the presence of chalcone moiety improves the AC conductance and dielectric properties of MONC doped polymer composite film.

Ag/ZnO Thin Film Nanocomposite Membrane Prepared by Laser-Assisted Method for Catalytic Degradation of 4-Nitrophenol.

Zinc oxide thin film (ZnO thin film) and a silver-doped zinc oxide nanocomposite thin film (Ag/ZnO thin film) were prepared by the technique of the pulsed laser deposition at 600 °C to be applicable as a portable catalytic material for the removal of 4-nitrophenol. The nanocomposite was prepared by making the deposition of the two targets (Zn and Ag), and it was analyzed by different techniques. According to the XRD pattern, the hexagonal wurtzite crystalline form of Ag-doped ZnO NPs suggested that the samples were polycrystalline. Additionally, the shifting of the diffraction peaks to the higher angles, which denotes that doping reduces the crystallite size, illustrated the typical effect of the dopant Ag nanostructure on the ZnO thin film, which has an ionic radius less than the host cation. From SEM images, Ag-doping drastically altered the morphological characteristics and reduced the aggregation. Additionally, its energy band gap decreased when Ag was incorporated. UV spectroscopy was then used to monitor the catalysis process, and Ag/ZnO thin films had a larger first-order rate constant of the catalytic reaction K than that of ZnO thin film. According to the catalytic experiment results, the Ag/ZnO thin film has remarkable potential for use in environmentally-favorable applications.

Metal Oxide Nanoparticles: An Effective Tool to Modify the Functional Properties of Thermally Stable Polyimide Films.

A series of polyimide/metal oxide (either ZrO2 or TiO2) nanocomposite films were fabricated based on two polymer matrices. The prepared films were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray diffraction analysis (XRD), and their thermal and mechanical properties were investigated with the use of thermogravimetric (TGA), differential thermal analysis (DTA), and thermomechanical analysis (TMA). We have found out that functional properties of the obtained materials are determined by a number of factors, not only the type, size, surface functionality, and concentration of the nanofiller, but also the chemical structure of the matrix polyimide. We have demonstrated some trends in the thermal and mechanical behavior of the materials depending on these features. The data could be of great interest in the areas where new materials with improved functional characteristics are needed.

Frequency and temperature dependent dielectric properties of polyvinyl alcohol/polystyrene sulfonic acid/cobalt oxide nanocomposite films

ABSTRACT Polyvinyl alcohol (PVA), polystyrene sulfonic acid (PSSA), and cobalt oxide (Co3O4) nanoparticles are used in the ease and low-cost solution casting method to prepare flexible nanocomposite films. Structural and morphological studies were carried out for the nanocomposites. Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) studies revealed an excellent interaction between the host polymer and Co3O4 nanoparticles. Scanning electron microscopy (SEM) was employed to study the surface morphology of the PVA/PSSA/Co3O4 nanocomposite films, which exhibited homogeneous dispersion of nanoparticles within the host matrix. Stress–strain curves were obtained to evaluate the mechanical properties of PVA/PSSA/Co3O4 nanocomposite films. The dielectric behavior of PVA/PSSA/Co3O4 nanocomposite films was examined by varying the content of Co3O4 nanoparticles in the frequency and temperature range of 100 Hz–1 MHz and 30–150°C, respectively. The 15 wt% of Co3O4 nanoparticles in the PVA/PSSA/Co3O4 nanocomposite films have a high dielectric constant (ɛ) of 511.66 and a relatively high dielectric loss (tan δ) of 1440.25 at low frequency and at 60°C, respectively. In addition, the high AC conductivity (σac) obtained for the 15 wt% of Co3O4 nanoparticles was found to be 1.66 × 10−5 Scm−1. The improvement in the dielectric performance of PVA/PSSA/Co3O4 nanocomposite films evidenced that they could be promising materials for microwave absorption applications.

Hybrid polypyrrole/copper/graphene oxide nanocomposite films synthesized via potentiostatic deposition with enhanced photovoltaic properties

Novel ternary nanocomposites films of Polypyrrole/copper/graphene oxide (PPy/Cu/GO) showed enhanced optical and electronic properties. In this study, PPy/Cu/GO films were synthesized with different GO load (0.0, 0.4, 0.6, and 0.8 wt%) using electrochemical deposition technique. The structural, optical and electrical properties of the composites were evaluated using X-Ray Diffraction (XRD) spectroscopy, UV–visible spectroscopy, Scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDX), and four-point probe methods. XRD results reveal that the GO was completely intercalated and dispersed uniformly in the nanocomposites. The results also revealed that the nanocomposite films are crystalline in nature, with distinct peaks corresponding to indexed miller indices. UV-visible analysis revealed that all of the nanocomposites showed good UV absorbance which was significant in the UV–Vis region of ≈450 nm. The energy band gap decreased with increase in GO load and was found within 3.46 to 2.25 eV, across the range of GO load which fall within the range of energy band gap for photovoltaic applications. The SEM results revealed that the nanocomposite films showed unevenly shaped structures with porous surface which increases with increasing GO loading, while the EDX result revealed the presence of carbon, oxygen nitrogen and copper as fundamental elements deposited. The nanocomposites' four-point probe analysis revealed slight increase in conductivity with low GO content. The incorporation of Cu and GO nanoparticles in PPy matrix provides a better balance and thus improved the photovoltaic properties of PPy/Cu/GO making them suitable for photovoltaic applications.

A Systematic Review on the Dielectric Response of Polyvinyl alcohol - Zinc Oxide Nanocomposites Films

This review article mainly discusses about the dielectric properties of polyvinyl alcohol (PVA)-zinc oxide (ZnO) nanocomposites films. Nanostructured ZnO is a semiconducting functional material. It has received a significant amount of attention due to its potential applications in various areas like antimicrobial, optoelectronic and sensor devices. Polyvinyl alcohol on the other hand offers an insulting polymer matrix with good dielectric breakdown strength and film forming properties. Incorporating semiconducting ZnO nanostructures into the insulating PVA matrix is of contemporary interest due to the intriguing dielectric response of the resulting nanocomposite films. Literature reports on the variations of several electrical parameters such as real and imaginary part of the complex permittivity, AC conductivity and complex impedance have been analysed here systematically. The effect of different ZnO nanostructure loading weight percentages, measurement temperature and frequency variations have been correlated with the corresponding changes in the dielectric constant, loss tangent values, dc conductivity contribution regime, hopping frequency, relaxation time and prevailing ac conduction mechanism of the nanocomposite films. Thus, this systematic review aims to provide a roadmap for the scientific community to optimize different parameters and enhance the functional properties of the PVA-ZnO nanocomposite films.

Polypyrrole/ Functionalized Multi-Walled Carbon Nanotube / Nickel Oxide Nanocomposites: Structural, Morphological, Optical and Composition Analysis Studies

Polypyrrole (PPy), functionalized multi-walled carbon nanotube (f-MWCNT), nickel oxide (NiO) nanocomposites (NCs) films did prepare by PLD technique. The weight percentage of PPy/ f-MWCNT varied from 1 to 5 wt.% whereas NiO fixed with 8wt.%. The nanocomposite films were characteristics by XRD, Raman, FTIR, SEM, and EDS. The XRD pattern shows that the films of (NCs) indicating the amorphous structure of PPy and polycrystalline cubic crystal of NiO and hexagonal phase of f-MWCNT. The dominant phase for (NCs) represented by (002) for f-MWCNT, NCs were shifted to different values of 2θ. Raman spectroscopy the characteristics peaks of (G-D) band at (1280,1320,1570,1610) and the intensity increases with concentration increase to the NCs. FTIR spectra of (NCs) films, refer that C2 has a prominent absorption peak at 1292 cm-1and C4 at 1550 cm-1indicated the spectrum of PPy/NiO and from C1 at 2360 cm−1and C4 at 709 cm−1indicated the spectrum of PPy/CNT. The morphological studies revealed that tubular surface structure at (C1, C3, and C5) and cluster branching in (C2, C4). It shows agglomeration particles and porosity for the surface of the (NCs) films. For all measurements, the (NCs) succeeded in making the nanoparticles (f-MWCNT/NiO) held together in the polymer (PPy) matrix indicating, that a good interlinkage between PPy, f-MWCNT, and NiO. Keywords: PPy/f-MWCNT/NiO nanocomposites, pulsed laser deposition, Nd:YAG Laser.

Development of Localized Surface Plasmon Resonance-Based Optical Fiber Biosensor for Immunoassay Using Gold Nanoparticles and Graphene Oxide Nanocomposite Film

In this study, the development of a reflected-type localized surface plasmon resonance (LSPR) based optical fiber biosensor is presented. The gold nanoparticles (AuNPs) and graphene oxide (GO) are sequentially modified on the surface of fiber probes to form a nanocomposite film using self-assembly method. Compared with AuNPs fiber probe, the refractive index sensitivity (RIS) of GO/AuNPs fiber probe is improved from 29.6 nm/RIU to 79 nm/RIU in the refractive index range from 1.33 to 1.38. After that, the fiber probes are immobilized with anti-mouse IgG for the immunoassay, and the response time is 30 minutes. Due to the advantages of good biocompatibility as well as physical and optical properties of GO, the GO/AuNPs fiber probe shows a quicker reaction and larger resonant wavelength shift, which are compared with AuNPs fiber probe in measuring different concentrations of mouse IgG. In addition, the GO/AuNPs fiber probe exhibits a better sensitivity (150.4 nm/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{g}$ </tex-math></inline-formula> mL <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−1</sup> ), linearity (R <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> = 0.998) and a lower limit of detection (4.3 ng/mL) in a low concentration of mouse IgG detection, which suggests that GO has huge potentials of biosensing applications in the future.

Physico-chemical, in-vitro cytotoxicity and antimicrobial evaluation of L-valine functionalised CuO NPs on polyvinyl alcohol and blended carboxymethyl cellulose films

ABSTRACT The novel L-valine functionalised polyvinyl alcohol (PVA)/CuO NPs and PVA/carboxymethyl cellulose (CMC)/Copper oxide nanocomposite (NCs) films were prepared by the solvent casting method. The required CuO NPs for NC films are prepared by the novel biogenic method using Euphorbia heterophylla plant leaves extract. Various spectroscopic techniques were employed for the characterisation of biogenic prepared CuO NPs and polymeric NC films prepared, namely X-ray diffraction, scanning electron microscopy and UV–visible spectroscopy. In-vitro cytotoxicity of the prepared NC films showed cell viability (%) >80% against human embryonic kidney cell lines (for films F3 & F4). In addition, the prepared NC films (F3 & F4) exhibited potent anti-bacterial and anti-fungal activity towards E. coli, S. aureus, C. tropicalis, and C. albicans. Furthermore, the prepared NCs films showed promising results in water contact angle (66.1%), water vapour permeability (28.09%), moisture retention capacity (94%), soil biodegradable test (42%), optical transparency (58.63%) and thermal properties. The obtained results suggested us the prepared PVA/CMC/CuO NPs films can be implemented in biomedical, environmental protection, and food packaging purposes.

High-performance supercapacitor electrode based on a layer-by-layer assembled maghemite/magnetite/reduced graphene oxide nanocomposite film

The actual relevance of supercapacitors for powering daily-life electronic devices as well as in future outer-space applications demands for innovative, high-performance and low-cost electrode materials. In this regard, the present contribution reports the electrochemical performance of a new supercapacitor electrode based on a layer-by-layer assembled maghemite/magnetite/reduced graphene oxide (MAG-RGO) nanocomposite film. The MAG-RGO electrode displays specific capacitance as high as 691.29 F g−1 at 5.6 A g−1. Its enhanced charge-storage ability is accomplished by proper adjustment of the electrode porosity with the Fe2+ to RGO mass ratio and the number of deposited MAG-RGO bilayers, which work synergistically in a combination of EDLC and pseudocapacitive behaviors. Fitting of the electrochemical impedance of different electrodes with a transmission line based equivalent circuit shows that the appropriate porosity is attained at Fe2+/RGO 5:1 and between 7 and 10 bilayers, when the electrode’s specific capacitance reaches its maximum and remains practically unaltered (87.5% of retention) over 10,000 charge–discharge cycles. Since the nanocomposite preparation and subsequent film assembly are relatively simple and inexpensive, while providing full control of its electrochemical behavior at the nanometer range, the MAG-RGO nanocomposite film electrode is a promising cost-effective alternative for future supercapacitor development and applications.

Preparation and spectroscopic studies of ZnO incorporated PVA nanocomposite films

Incorporation of zinc oxide nanoparticles (ZnO NPs) into a polyvinyl alcohol (PVA) base matrix forms its nanocomposite films. Their morphological, spectroscopic, and thermal properties were studied using X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Ultraviolet–visible Spectrophotometry (UV–vis) spectroscopy, and Differential Scanning Calorimetry (DSC) methods. In this investigation, various weight percentages (0, 2, 4, 6, and 8 wt%) of ZnO NPs were incorporated into PVA using the solution casting method. According to XRD studies, the ZnO nanoparticles' original structure was preserved in the Polyvinyl alcohol–Zinc oxide nanocomposite (PVA-ZnO NC) films, and the crystallinity of the PVA-ZnO NC films was increased. The SEM images confirmed that the ZnO NPs were uniformly spread on the surface film. The UV–visible investigations were carried out, and the values of the refractive index, Urbach energy, direct bandgap, and indirect bandgap were assessed. The loading of 0 to 8 wt% of ZnO NPs in the PVA matrix resulted in a significant change in direct bandgap from 6.16 eV to 5.61 eV, indirect bandgap from 5.89 eV to 5.24 eV, Urbach energy from 0.428 eV to 0.538 eV, linear refractive index from 1.64 to 2.67, and extinction coefficient from 0.00016 to 0.00065. These results showed that the spectroscopic properties of PVA-ZnO NC films were modified considerably with small loadings of ZnO NPs in the PVA matrix due to cross-linking formation between the nanoparticles and the polymer. The DSC results demonstrated that increasing the weight percentage of ZnO NPs had no effect on the glass transition temperature or melting point of the composite films.

Synthesis and characterization of Fe2O3 nanoparticles incorporated PVA nanocompositefilms

Polyvinyl alcohol–iron oxide nanocomposite (PVA-Fe2O3 NC) films have been formed when iron oxide nanoparticles (Fe2O3 NPs) are incorporated into a polyvinyl alcohol (PVA) base matrix. In this study, for the preparation of a series of PVA-Fe2O3 NC films, different weight percentages (0, 2, 4, 6, and 8 wt. %) of Fe2O3 NPs have been added into the PVA solution using the solution cast method. The morphological and spectroscopic properties of the PVA-Fe2O3 NC films have been studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), and ultraviolet-visible spectrophotometry (UV-Vis) spectroscopy techniques. XRD studies reveal that the original structure of the Fe2O3 NPs is preserved in the PVA-Fe2O3 NC films, and the crystallinity of the PVA-Fe2O3NC films has been increased. The SEM images confirm that the Fe2O3 NPs have been homogeneously distributed in 3-dimension with dots and rod-like structures. The UV-visible investigations have been carried out for the series of PVA-Fe2O3 NC films, which result in a significant change in opto-electronic properties. With an increasing weight percentage of Fe2O3 NPs in the PVA-Fe2O3 NC films, the direct bandgap decreased from 5.39 eV to 5.01 eV, the indirect bandgap decreased from 4.73 eV to 3.27 eV, the Urbach energy increased from 0.428 eV to 0.538 eV, the linear refractive index increased from 1.63 to 5.86, and the extinction coefficient increased from 1.86 X 10-6 to 1.74 X 10-5. These results have shown that the spectroscopic properties of PVA-Fe2O3 NC films are modified considerably with the small addition of Fe2O3 NPs in the PVA matrix, which are useful for optoelectronic applications.