Tuning optical, dielectric, and electrical properties of Polyethylene oxide/Carboxymethyl cellulose doped with mixed metal oxide nanoparticles for flexible electronic devices

Impact of nanocurcumin on mechanical, optical and electrical properties of chitosan/polyvinyl alcohol blend nanocomposites for sustainable applications

Blend nanocomposites of chitosan (CS) and polyvinyl alcohol (PVA), reinforced with varying concentrations of nanocurcumin (NC), were synthesized using a simple green method. The impact of NC on the optical, structural, and morphological characteristics of the blend nanocomposite films was evaluated through different analytical techniques, including FT-IR, XRD, UV-Vis spectroscopy, scanning electron microscopy, TGA, universal testing machine and electrical measurements. The distinctive peaks observed in the FT-IR and XRD analysis confirmed the successful incorporation of NC into the PVA/CS (PC) blend matrix. UV spectroscopy revealed that absorption increased with nanoparticle concentration, with the 9 wt% sample showing the highest intensity, which correlates with its low optical bandgap energy. SEM analysis showed that nanoparticles influenced the surface morphology of the PC matrix, with the most uniform particle distribution observed in the 9 wt% sample. Increasing NC content improved the thermal stability of the PC films. The nanocomposite with 9 wt% NC exhibited a significant improvement in tensile strength, increasing by 35 % compared to neat PC, along with an excellent Young's modulus. The temperature-dependent dielectric constant, AC conductivity, and impedance were analyzed across different NC loadings. The maximum conductivity and dielectric constant were found in the 9 wt% nanocomposites. The superior tensile strength, Young's modulus, thermal stability, conductivity, dielectric constant, and optical properties of the PC blend nanocomposites highlight their potential for use in eco-friendly, flexible optoelectronic devices.

The Investigation of Structural, Optical and Thermal Properties of Nickel Doped CeO2 Integrated PVC Nanocomposite

PVC nanocomposite (NC) films with cubic CeO2 and Ni-doped CeO2 (NDC) have been prepared using a conventional solution-casting technique. The prepared films were characterized with FT-IR spectrometer, X-ray diffraction (XRD), and scanning electron microscopy (SEM). The optical and thermal properties of the films were evaluated using a UV-visible spectrophotometer and TGA/DSC. The optical study revealed a decrease in optical band gap energies (4.19 to 4.06 eV) whereas the increase in other optical constraints such as optical conductivity, Urbach energy, dispersion energy, refractive index, and dielectric constant of PVC NCs than pristine PVC was observed. The XRD patterns showed the presence of cubic crystalline NDC with a relatively narrower principal diffraction peak in the PVC matrix and the nonexistence of unexpected vibrational peaks in the FTIR spectra of PVC NCs confirmed the successful incorporation of nanostructured CeO2 and NDC into PVC. Thermogravimetric analysis showed the higher thermal stability of NDC/PVC NC than PVC whereas differential scanning calorimetry declared no significant change in the glass transition temperature (Tg) of the NCs. Moreover, a good dispersion of Ni-doped CeO2 nanofiller was noticed in scanning electron micrographs.

Modulating the properties of carboxymethyl chitosan/polyethylene oxide nanocomposites with aluminium oxy hydroxide: A comprehensive study

This study explores the eco-friendly synthesis of carboxymethyl chitosan/polyethylene oxide/γ-aluminium oxyhydroxide (CMCS/PEO/γ-AlOOH) nanocomposite films through a sustainable, green preparation method. The CMCS/PEO/γ-AlOOH nanocomposites were characterized through X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) to analyze their structural and morphological properties. The emergence of distinct peaks of γ-AlOOH in XRD and FTIR spectra indicated the strong interaction between γ-AlOOH and the blend. Morphological analysis revealed significant changes in the surface characteristics of the pristine blend upon incorporation of γ-AlOOH. Thermogravimteric analysis (TGA) confirmed the improved thermal stability of the nanocomposites, while differential scanning calorimetry (DSC) revealed changes in the glass transition temperature proportional to the γ-AlOOH content. The nanocomposite films demonstrated enhanced mechanical properties, exhibiting a 39.6 % increase in tensile strength at a 5 wt% γ-AlOOH loading. The temperature-dependent dielectric constant, loss tangent, AC conductivity and impedance were analyzed at varying loadings of γ-AlOOH. The 7 wt% γ-AlOOH nanocomposites showed the highest conductivity (1.23 × 10-6 S/cm at 1 MHz) and dielectric constant (244 at 100 Hz) at ambient temperature. The CMCS/PEO/γ-AlOOH nanocomposite's superior tensile strength, thermal stability, glass transition temperature, conductivity, and dielectric constant make it a strong candidate for eco-friendly, flexible electronic devices.

Chemical and Resistive Switching Properties of Elaeodendron buchananii Extract-Carboxymethyl Cellulose Composite: A Potential Active Layer for Biodegradable Memory Devices

Biodegradable electronic devices play a crucial role in addressing the escalating issue of electronic waste accumulation, which poses significant environmental threats. In this study, we explore the utilization of a methanol-based extract of the Elaeodendron buchananii plant blended with a carboxymethyl cellulose biopolymer to produce a biodegradable and environmentally friendly functional material for a resistive switching memory system using silver and tungsten electrodes. Our analyses revealed that these two materials chemically interact to generate a perfect composite with near semiconducting optical bandgap (4.01 eV). The resultant device exhibits O-type memory behavior, with a low ON/OFF ratio, strong endurance (≥103 write/erase cycles), and satisfactory (≥103) data retention. Furthermore, through a comprehensive transport mechanism analysis, we observed the formation of traps in the composite that significantly improved conduction in the device. In addition, we established that altering the voltage amplitude modifies the concentration of traps, leading to voltage amplitude-driven multiple resistance states. Overall, our findings underscore the potential of functionalizing polymers that can be functionalized by incorporating plant extracts, resulting in biodegradable and nonvolatile memory devices with promising performance metrics.

A comparative study of PMMA/PEG polymer nanocomposites doped with different oxides nanoparticles for potential optoelectronic applications

PMMA/PEG and PMMA/PEG doped with SiO2, TiO2, and Al2O3 were fabricated using the solution-casting technique. The composites were characterized by X-ray diffraction and scanning electron microscopy (FE-SEM), which revealed that the amorphous nature of PMMA/PEG blend doped with Al2O3 was hindered by the crystalline nature of those doped with SiO2 and TiO2. The absorption of PMMA/PEG blend doped with Al2O3 is higher, band gap energies were decreased from 4.90 eV for PMMA/PEG blend to 4.03 eV, 3.09 eV, and 2.09 eV for SiO2, TiO2, and Al2O3 doped PMMA/PEG blend, respectively. The dielectric constant, ε' has a high value (2 × 104) for samples PMMA/PEG and SiO2/PMMA/PEG. While dielectric lossε ″ -values decreased to < 100 for TiO2/PMMA/PEG and Al2O3/PMMA/PEG. Further, the fabricated composite SiO2/PMMA/PEG led to improvement the optical and dielectric properties compared with PMMA/PEG for optoelectronic such as manufacturing of optical fiber cables application. The results show TiO2/PMMA/PEG and Al2O3/PMMA/PEG are multifunctional can be used as low-permittivity nanodielectric and substrates to design the next generation of flexible electronic devices.

Preparation and Properties of Polyaniline/Hydroxypropyl Methylcellulose Composite Conductive Thin Films

In this work, a chemical grafting polymerization method was employed to synthesize EHPMC-g-PANI self-supporting films. Polyaniline (PANI) was grafted onto hydroxypropyl methylcellulose (HPMC) modified with epichlorohydrin (EPHMC) to obtain an EHPMC-g-PANI aqueous dispersion, which was subsequently dried to form the self-supporting films. The introduction of HPMC, with its excellent film-forming ability and mechanical strength, successfully addressed the poor film-forming ability and mechanical properties intrinsic to PANI. Compared to in situ polymerized HPMC/PANI, the EHPMC-g-PANI exhibited significantly improved storage stability. Moreover, the fabricated EHPMC-g-PANI films displayed a more uniform and smoother morphology. The conductivity of all the films ranged from 10-2 to 10-1 S/cm, and their tensile strength reached up to 36.1 MPa. These results demonstrate that the prepared EHPMC-g-PANI holds promising potential for applications in various fields, including conductive paper, sensors, and conductive inks.

Effect of chromium doping on the band gap tuning of titanium dioxide thin films for solar cell applications

A simple and inexpensive spray pyrolysis deposition (SPD) approach was used to produce TiO2 and Cr (2-8) at.%-doped TiO2 thin films. To explore the morphological features of the films, FE-SEM micrographs were used and found that 6 and 8 at.% TiO2:Cr films had fibrous patterns with diameters of 0.45 and 0.78 μm, respectively, while the remainder of the films were agglomerated particles. From X-ray diffraction investigation, it was found that the TiO2 thin films had an anatase crystal phase (tetragonal) up to 6 at.% Cr doping, while an anatase-rutile mixed crystalline phase was identified for 8 at.% Cr doping. The crystallite size of the pristine TiO2 film was 35 nm, while for TiO2:Cr films, it ranges from 35 to 46 nm. The Fizeau fringes technique was employed to measure the thickness of the TiO2 film and 165 nm was found for pristine TiO2 and 164-180 nm for TiO2:Cr films. UV-visible spectroscopy was used to study optical properties such as absorbance, refractive index, optical band gap, dielectric constant, and optical conductivity. As the Cr concentration increases, the optical band gap decreases from 3.40 eV to 2.70 eV. Using the four-point probe method, it was found that the resistivity changes with temperature and is also affected by the Cr content.

Polyelectrolytes: From Seminal Works to the Influence of the Charge Sequence

We propose a selected tour of the physics of polyelectrolytes (PE) following the line initiated by de Gennes and coworkers in their seminal 1976 paper. The early works which used uniform charge distributions along the PE backbone achieved tremendous progress and set most milestones in the field. Recently, the focus has shifted to the role of the charge sequence. Revisited topics include PE complexation and polyampholytes (PA). We develop the example of a random PE in poor solvent forming pearl-necklace structures. It is shown that the pearls typically adopt very asymmetric mass and charge distributions. Individual sequences do not necessarily reflect the ensemble statistics and a rich variety of behaviors emerges (specially for PA). Pearl necklaces are dynamic structures and switch between various types of pearl-necklace structures, as described for both PE and PA.

UV filters and high refractive index materials based on carboxymethyl cellulose sodium and CuO@ZnO core/shell nanoparticles

Nanoparticles have substantially contributed to the field of skincare products with ultraviolet (UV) filters to preserve human skin from sun damage. Thus, the current study aims to develop new polymer nanocomposites for the efficient block of UV light that results from the stratospheric ozone layer loss. Co-precipitation method was used to successfully synthesis CuO@ZnO core/shell NPs with a well-crystalline monoclinic CuO core and wurzite ZnO shell. Using the casting method, core/shell NPs were successfully introduced to carboxymethyl cellulose sodium (CMC). The CMC nanocomposites displayed considerably broader optical response extending from near-ultraviolet to visible light, which was likely due to heterojunction between the p-CuO core and n-ZnO shell and defects originating from the synthetic process. The transmittance of pure CMC in the UV, visible, and near IR regions is significantly reduced with the addition of 2 and 4 wt% of CuO@ZnO core/shell NPs to CMC. 99% of UV light is absorbed when 4 wt% of CuO@ZnO core/shell NPs are added. The addition of different concentrations of CMC nanocomposite to one of the sunblock in Egyptian market were studied and showing the highest Sun Protection Factor of 22. Moreover, optical dispersion parameters and refractive index were improved strongly with core/shell NPs addition.

A Study on the 3D Deformation Behavior of Porous PDMS Flexible Electronic Composite Films Stretched under Different Temperatures

Flexible electronic films need to be applied in different ambient temperatures. The porous substrate of the composite film enhances air permeability. The lifespan of these composite films is significantly affected by variations in temperature and substrate porosity. To explore the impact of temperature and porosity on the performance of composite films, we developed a 3D deformation detection system utilizing the advanced three-dimensional digital image correlation (3D-DIC) method. This system enabled us to observe and analyze the 3D deformation behaviors of porous polydimethylsiloxane (PDMS) flexible composite films when they are subjected to uniaxial stretching at different temperatures. We proposed employing two parameters, namely the strain fluctuation coefficient (M) and off-plane displacement (w), to characterize the 3D deformation of the films. This holistic characterization of deformation through the combined utilization of parameters M and w held greater significance for composite films compared to the conventional practice of solely measuring mechanical properties like the elastic modulus. Through experimental analysis, we discovered that as the temperature increased, the M value of the film decreased while the w value increased for the same stretching distance. Furthermore, the porosity of the composite film depended on the doping mass ratio of PDMS to deionized water during the fabrication process. Specifically, when the ratio was set at 6:1, the composite film exhibited the smallest M value and w value, and the highest air permeability. Additionally, the 3D deformation behavior remained stable across different temperatures for this specific ratio. Moreover, our findings unveiled a remarkable association between the parameter w and the resistance value of the device. These findings provide valuable insights for optimizing the fabrication process of porous PDMS flexible electronic composite films.

Bio-based antimicrobial food packaging films based on hydroxypropyl starch/polyvinyl alcohol loaded with the biosynthesized zinc oxide nanoparticles

In the last decades, bio-based active food packaging materials have received much attention. It is known that the utilization of traditional materials for food packaging applications lack some critical characteristics such as resistance to the harmful microbes that cause a damage to the preserved foods. Therefore, the current study aimed to find an alternative packaging films comprises an efficient biopolymers. This research work was designed to prepare film mats using hydroxypropyl starch (HPS), polyvinyl alcohol (PVA), palmitic acid (PA) and biosynthesized zinc oxide nanoparticles (ZnONPs). The fabricated films were coded as 1H, 2H, 3H and 4H based on the utilized concentration of ZnONPs. The biosynthesized ZnONPs and the bio-based films loaded with ZnONPs were characterized. The results revealed that ZnONPs exhibited nearly spherical shape and size ∼40 nm. The surface structure of the produced bioactive packaging films exhibited smooth with homogeneous features, excellent mechanical and thermal stability properties. The prepared bioactive packaging film loaded with ZnONPs (4H) exhibited superior antibacterial activity among other films against Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 25923 with inhibition zones 15.1 ± 0.76 and 12.1 ± 0.71 mm respectively. Correspondingly, packing film 4H exhibited potential antifungal activity toward Aspergillus niger RCMB 02724, A. flavus RCMB 02782, Penicillium expansum IMI 89372 and Fusarium oxysporum RCMB 001004 with inhibition zones (16 ± 1.0, 22 ± 0.90, 18.0 ± 1.1 and12.3 ± 0.57 mm respectively). Moreover, all prepared films did not show cytotoxicity on the normal cell line (Wi38) and recorded biodegradability properties that reached around 85 % after four weeks in soil. Based on these results, the antimicrobial films comprising HPS/PVA and loaded with the biosynthesized ZnONPs can be considered as a suitable film for food packaging purposes.

Distinct Optical and Structural (Nanoyarn and Nanomat-like Structure) Characteristics of Zinc Oxide Nanofilm Derived by Using Salvia officinalis Leaves Extract Made without and with PEO Polymer

This paper reports the optical properties of zinc oxide nanofilm fabricated by using organic natural products from Salvia officinalis leaves (SOL) extract and discusses the effect of the nanocrystal (NC) structure (nanoyarn and nanomat-like structure) on nanofilm optical properties. The surface-active layer of the nanofilm of ZnO nanoparticles (ZnO NPs) was passivated with natural organic SOL leaves hydrothermally, then accumulated on zinc oxide nanorods (ZnO NRs). The nanofilms were fabricated (with and without PEO) on glass substrate (at 85 °C for 16 h) via chemical solution deposition (CSD). The samples were characterized by UV-vis, PL, FESEM, XRD, and TEM measurements. TEM micrographs confirmed the nucleation of ZnO NPs around 4 nm and the size distribution at 1.2 nm of ZnO QDs as an influence of the quantum confinement effect (QCE). The nanofilms fabricated with SOL surfactant (which works as a capping agent for ZnO NPs) represent distinct optoelectronic properties when compared to bulk ZnO. FESEM images of the nanofilms revealed nanoyarn and nanomat-like structures resembling morphologies. The XRD patterns of the samples exhibited the existence of ZnO nanocrystallites (ZnO NCs) with (100), (002), and (101) growth planes. The nanofilms fabricated represented a distinct optical property through absorption and broad emission, as the optical energy band gap reduced as the nanofilms annealed (at 120 ℃). Based on the obtained results, it was established that phytochemicals extracted from organic natural SOL leaves have a distinct influence on zoic oxide nanofilm fabrication, which may be useful for visible light spectrum trapping. The nanofilms can be used in photovoltaic solar cell applications.

Enhanced Emulsifying Ability of Deoxycholate through Dynamic Interaction with Layered Double Hydroxide

The emulsifying ability of the naturally occurring surfactant deoxycholic acid (DCA) was improved by dynamic interaction with nanometric layered particles, layered double hydroxide (LDH). As DCA molecules are rigid due to the facial configuration of hydrophobic-hydrophilic groups, they tend to form molecular aggregation in an acidic condition or imbalanced water-lipid ratios. In this study, the homogeneous hybrids of DCA and LDH were obtained by the in situ growth of LDH at a DCA molecule. The DCA-LDH hybrid successfully prevented the molecular aggregation of DCA at an acidic pH and imbalanced water-to-oil ratio. The dynamic light scattering showed that the hydrodynamic radius of micelle in the emulsion made with DCA-LDH maintained its small size (<500 nm), while upon pH change and dilution with water, that made with DCA only uncontrollably increased up to ~3000 nm. The polydispersity index value of the DCA-LDH emulsion remained constant (<0.3) after the pH change and dilution with water, indicating the high stability of the formulation. Furthermore, time-dependent turbidity monitoring revealed that the DCA-only formulation suffered from serious coalescence and creaming compared with the DCA-LDH formulation. It is suggested that the dynamic interaction between LDH layers and DCA prevented molecular aggregation under unfavorable conditions for the oil-in-water emulsion.