Synthesized PANI/CeO2 Nanocomposite Films for Enhanced Anti-Corrosion Performance.

This study introduces a novel nanocomposite coating composed of PANI/CeO2 nanocomposite films, aimed at addressing corrosion protection needs. Analysis through FTIR spectra and XRD patterns confirms the successful formation of the nanocomposite films. Notably, the PANI/CeO2 nanocomposite films exhibit a hydrophilic nature. The bandgap energy of the PANI composite film is measured to be 3.74 eV, while the introduction of CeO2 NPs into the PANI matrix reduces the bandgap energy to 3.67 eV. Furthermore, the electrical conductivity of the PANI composite film is observed to be 0.40 S·cm-1, with the incorporation of CeO2 NPs leading to an increase in electrical conductivity to 1.07 S·cm-1. To evaluate its efficacy, electrochemical measurements were conducted to assess the corrosion protection performance. Results indicate a high protection efficiency of 92.25% for the PANI/CeO2 nanocomposite film.

The Role of Polymer Chain Stiffness and Guest Nanoparticle Loading in Improving the Glass Transition Temperature of Polymer Nanocomposites.

The impact of polymer chain stiffness characterized by the bending modulus (kθ) on the glass transition temperature (Tg) of pure polymer systems, as well as polymer nanocomposites (PNCs), is investigated using molecular dynamics simulations. At small kθ values, the pure polymer system and respective PNCs are in an amorphous state, whereas at large kθ values, both systems are in a semicrystalline state with a glass transition at low temperature. For the pure polymer system, Tg initially increases with kθ and does not change obviously at large kθ. However, the Tg of PNCs shows interesting behaviors with the increasing volume fraction of nanoparticles (fNP) at different kθ values. Tg tends to increase with fNP at small kθ, whereas it becomes suppressed at large kθ.

Physicochemical Properties of Organic Molecular Ferroelectric Diisopropylammonium Chloride Thin Films.

We fabricated ferroelectric films of the organic molecular diisopropylammonium chloride (DIPAC) using the dip-coating technique and characterized their properties using various methods. Fourier-transform infrared, scanning electron microscopy, and X-ray diffraction analysis revealed the structural features of the films. We also performed ab-initio calculations to investigate the electronic and polar properties of the DIPAC crystal, which were found to be consistent with the experimental results. In particular, the optical band gap of the DIPAC crystal was estimated to be around 4.5 eV from the band structure total density-of-states obtained by HSE06 hybrid functional methods, in good agreement with the value derived from the Tauc plot analysis (4.05 ± 0.16 eV). The films displayed an island-like morphology on the surface and showed increasing electrical conductivity with temperature, with a calculated thermal activation energy of 2.24 ± 0.03 eV. Our findings suggest that DIPAC films could be a promising alternative to lead-based perovskites for various applications such as piezoelectric devices, optoelectronics, sensors, data storage, and microelectromechanical systems.

Large Negative Poisson's Ratio and Anisotropic Mechanics in New Penta-PBN Monolayer.

The scarce negative Poisson's ratio (NPR) in a two-dimensional (2D) material is an exceptional auxetic property that offers an opportunity to develop nanoscale futuristic multi-functional devices and has been drawing extensive research interest. Inspired by the buckled pentagonal iso-structures that often expose NPR, we employ state-of-the-art first-principles density functional theory calculations and analyses to predict a new 2D metallic ternary auxetic penta-phosphorus boron nitride (p-PBN) with a high value of NPR. The new p-PBN is stable structurally, mechanically, and dynamically and sustainable at room temperature, with experimental feasibility. The short and strong quasi sp3-hybridized B-N bond and unique bond variation and geometrical reconstruction with an applied strain allow p-PBN to inherit a high value of NPR (-0.236) along the (010) direction, the highest among any other ternary penta iso-structures reported to date. Despite having a small elastic strength, the highly asymmetric Young's modulus and Poisson's ratio along the (100) and (010) directions indicate large anisotropic mechanics, which are crucial for potential applications in nanomechanics and nanoauxetics.

Computational and experimental characterizations of annealed Cu2ZnSnS4 thin films.

We report on the synthesis and characterization of Cu2ZnSnS4 (CZTS) thin films prepared at different annealing temperatures using the sol-gel method and deposited on glass substrates using the immersing method. The XRD analysis demonstrates that the films annealed at 450 °C exhibit the most stable tetrahedral kesterite structure. Computationally, the Vienna ab initio simulation package (VASP) has been implemented to calculate critical structural properties of as-prepared CZTS) thin films and compared with those extracted from the XRD patterns. An excellent agreement is obtained between the calculated and measured structural parameters. Optical measurement of key optical parameters of annealed CZTS thin films shows a drastic manipulation of all-optical properties compared to the as-prepared thin films. In particular, an optical band gap of 1.62 eV obtained for annealed CZTS thin films at 450 °C makes them eligible to be potential candidates for thin film-based high-efficiency solar cells. Calculations of elastic properties of annealed thin films reveal that crystallite size increases and microstrain decrease compared with those of as-prepared thin films. The sheet resistance of annealed CZTS thin films exhibits a significant decline as the annealing temperature is increased. The electrical properties of annealed CZTS thin films could match some conductors. Remarkably, at 450 °C annealing temperature, the sheet resistance decreases to 74 Ω.cm-1 indicating the possibility of using the annealed CZTS thin films for efficient and low cost solar cell applications.

Synthesis and Characterization of Thin Films Based on Azobenzene Derivative Anchored to CeO2 Nanoparticle for Photoswitching Applications.

Azobenzene has attracted substantial attention as a photoswitchable molecule since its applications range from energy and data storage to biomedical applications. This work reports a new type of thin-film based on azobenzene derivative anchored to cerium oxide nanoparticles CeO2 NPs for photoswitching applications. The trans-cis isomerization and reverse isomerization occur by UV-light exposure and thermal relaxation process, respectively. The photoisomerization and reverse isomerization kinetics for CeO2 NPs-MR thin films are studied, investigated, and analyzed using UV-Vis absorbance spectra, FTIR spectroscopy, XRD, and scanning electron microscopy (SEM), in addition to differential scanning calorimetry (DSC) measurement to study the energy storage capacity. The results found that anchoring azobenzene to CeO2 NPs is successful in multisource storage of solar energy applications.

Synthesis of Optically Tunable and Thermally Stable PMMA-PVA/CuO NPs Hybrid Nanocomposite Thin Films.

We report the synthesis and comprehensive characterization of polymethylmethacrylate (PMMA)/polyvinylalcohol (PVA) polymeric blend doped with different concentrations of Copper oxide (CuO) nanoparticles (NPs). The PMMA-PVA/CuO nanocomposite hybrid thin films containing wt.% = 0%, 2%, 4%, 8%, and 16% of CuO NPs are deposited on glass substrates via dip-coating technique. Key optical parameters are measured, analyzed, and interpreted. Tauc, Urbach, Spitzer-Fan, and Drude models are employed to calculate the optical bandgap energy (Eg) and the optoelectronic parameters of PMMA-PVA/CuO nanocomposites. The refractive index and Eg of undoped PMMA-PVA are found to be (1.5-1.85) and 4.101 eV, respectively. Incorporation of specific concentrations of CuO NPs into PMMA-PVA blend leads to a considerable decrease in Eg and to an increase of the refractive index. Moreover, Fourier Transform Infrared Spectroscopy (FTIR) transmittance spectra are measured and analyzed for undoped and doped polymeric thin films to pinpoint the major vibrational modes in the spectral range (500 and 4000 cm-1) as well as to elucidate the nature of chemical network bonding. Thermogravimetric analysis (TGA) is conducted under appropriate conditions to ensure the thermal stability of thin films. Doped polymeric thin films are found to be thermally stable below 105 °C. Therefore, controlled tuning of optoelectronic and thermal properties of doped polymeric thin films by introducing an appropriate concentration of inorganic fillers leads to a smart design of scaled multifunctional devices.

Hospital preparedness and management of pediatric population during COVID-19 outbreak.

With the recent pandemic of Coronavirus disease-2019 (COVID-19), there has been a higher number of reported cases in children more than to the prior Corona Virus-related diseases, namely, severe acute respiratory syndrome and the Middle East respiratory syndrome. The rate of COVID-19 in children is lower than adults; however, due to high transmission rate, the number of reported cases in children has been increasing. With the rising numbers among children, it is imperative to develop preparedness plans for the pediatric population at the hospital level, departmental level, and patient care areas. This paper summarizes important considerations for pediatric hospital preparedness at the hospital level that includes workforce, equipment, supply; capacity planning, and infection prevention strategies, it also span over the management of COVID-19 pediatric patients in high-risk areas such as critical care areas, Emergency Department and operative rooms.

Optical, Structural, and Crystal Defects Characterizations of Dip Synthesized (Fe-Ni) Co-Doped ZnO Thin Films.

Sol-gel technique is used to synthesize as-grown zinc oxide (ZnO) and iron-nickel (Fe-Ni) co-doped ZnO thin films deposited on glass substrates using dip coating technique. The structural properties and crystal imperfections of as-prepared thin films are investigated. We performed the structural analysis of films using X-ray diffraction (XRD). The XRD analysis reveal that the as-prepared films exhibit wurtzite structure. Furthermore, XRD-line profile analysis is performed to study the correlation between structural properties and imperfections of the nanocomposite thin films. The crystallite size and microstrains parameters are predicted using the Williamson-Hall method. We found that the crystallites size increases as the co-doped (Fe-Ni) concentration is increased. However, microstrains of the nanocomposite films decreases as (Fe-Ni) concentration is increased. The optical properties of the (Fe-Ni) co-doped nanocomposite films are investigated by performing UV-Vis (250 nm-700 nm) spectrophotometer measurements. We found that as the (Fe-Ni) concentration level is steadily increased, transmittance of the undoped ZnO thin films is decreased. Remarkably, refractive index of undoped ZnO thin films is found to exhibit values extending from 1.55 to1.88 that would increase as (Fe-Ni) concentration is increased.

Crystallographic, vibrational modes and optical properties data of α-DIPAB crystal.

The Crystallographic data of the α-DIPAB sample was measured using powder X-ray diffraction (PXRD). The crystal structure was also optimized using density functional based method. The calculations were performed both including van der Waals (vdW) interactions and excluding them to quantify the effects of vdW interaction on the crystal formation. The vibrational modes of DIPAB crystal corresponding to the Bromine deficient samples are calculated and presented. These show the origin of drastic change in dielectric response in Br deficient samples as compared to the ideal stoichiometric DIPAB crystal (Alsaad et al. 2018) [4]. Optical properties of an idealα-DIPAB were calculated using GGA and HSE06 hybrid functional methods implemented in VASP package. We mainly calculated the real and imaginary parts of the frequency-dependent linear dielectric function, as well as the related quantities such as the absorption, reflectivity, energy-loss function, and refractive index of α-DIPAB in the energy window of (0-12) eV.

Optimisation and characterisation of various extraction conditions of phenolic compounds and antioxidant activity in olive seeds.

This study was conducted to optimise the extraction conditions of phenolic compounds to evaluate antioxidant extraction parameters and to identify the major free and bound phenolic compounds in olive seeds. The results obtained using methanol as an extraction solvent for olive seeds indicated that the optimised total phenolic content and antioxidant activity were obtained at an extraction time of 12 h, an extraction temperature of 70°C and an extraction cycle of three stages. The correlation coefficient between total phenolic compounds and antioxidant activities was positive (R² = 0.83). The major finding is that the predominant phenolic compounds in olive seeds were present in free form. However, a small percentage of the bound phenolic compounds was found in olive seeds compared to that of the free phenolic compounds. This study recommends that olive seeds with optimised extraction conditions (i.e. optimised correlation between phenolic compound contents and antioxidant activities) can be used as potential food additive candidates in functional, nutraceutical and pharmaceutical industries.