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The electrical and networking industries are increasingly reliant on high-frequency ferrite nanocomposites, which are produced using ferrite and a polyaniline binder. In the present study, polyaniline is prepared by in-situ, while the ferrite is synthesized by adopting sol-gel process. The X-ray diffraction (XRD) analysis showed that all the samples (except PANI) possessed spinel structure. When spinel ferrite is blended with the polymer matrix, the crystallite size increased from 19 nm to 61 nm. Combining polyaniline with ferrites leads to a decreasing trend in the dielectric parameters (ε‘, ε“). Hysteresis loop analysis was conducted to evaluate the materials’ ferromagnetic properties. The saturation magnetization (Ms), remanent magnetization (Mr), and coercivity (Hc) all increased as the concentration of ferrite has been increased. The direct current (dc) resistivity and activation energy of a sample containing ferrites and polyaniline also increased. These all parameters suggested that FP-4 may be suitable for high-frequency applications. Graphical Abstract It illustrates that the dc resistivity of all samples are directly related to temperature, as heat causes charge carriers to move more. At room temperature, ferrites conduct electricity due to defects, but at a certain temperature, their primary mode of conductance is polaron hopping. The Verwey’s hypothesis explains that ferrites conduct electricity because electrons hop from one ion of the identical element to another that is randomly distributed across several crystalline lattice sites and has a different valence electron configuration. Highlights Ferrite and polyaniline samples were used to synthesize the nanocomposites using the sol-gel/in-situ technique. X-ray diffraction analysis revealed that the spinel crystals had a crystallite size of 19–61 nm. An increase from 25 emu/g to 52 emu/g in saturation Ms and an increase from 19 to 219 Oe in coercivity were observed, when the amount of spinel increases in the nanocomposite. The dielectric characteristics were frequency-dependent at lower frequencies, but frequency-invariant at higher frequencies.

In this study, silk fibroin as a highly promising naturally occurring biopolymer extracted from silkworm cocoon is applied to mechanically reinforce silica aerogels. To this aim, two different approaches for the incorporation of silk fibroin into the silica network are compared: (1) a one-step acid catalyzed and (2) a two-step acid-base catalyzed sol–gel reaction. The total organosilane concentration, as well as the SF to silane mass fractions, regulated the hybridization process to proceed either through a one-step or two-step sol–gel reaction. In both processes, for an efficient chemical mixing the silk fibroin components with the silane phase, a silane coupling agent, 5-(trimethoxysilyl) pentanoic acid (TMSPA), comprising carboxylic acid groups and a pentyl hydrocarbon chain has been used. For a low organosilane content (3.4 mmol) along with a high SF to silane mass ratio (15–30%), the gelation of the silane and silk fibroin phases took place in a one-pot/one-step process in the presence of an acid catalyst in an entirely aqueous system. In the two-step synthesis approach, which was applied for high initial silane contents (17 mmol), and low SF to silane mass ratios (1–4%), first, the gelation of the silk fibroin phase was triggered by addition of an acid catalyst followed by a more pronounced condensation of the silane catalyzed by the addition of the base. Both synthesis approaches led to materials with promising mechanical properties—being 1) the one-step process resulting in gels with much better compressibility (up to 70% of strain), low density (0.17–0.22 g cm −3 ) and three orders of magnitude improvement in the Young’s modulus (13.5 MPa) compared to that of the pristine silica aerogel but with rather high shrinkage (30–40%). The two-step process in principle could result in the hybrid aerogel with interesting bulk density (0.17–0.28 g cm −3 ) with lower shrinkage (10%), but the resultant aerogel was stiff and fragile. Also, both approaches led to a significant reduction in the time required to prepare strong hybrid aerogels compared to conventional hybrid polymer-silica aerogels with the utilization of an entirely aqueous synthesis approach for a wide range of applications. Highlights Silk fibroin (SF) biopolymer is an interesting biopolymer for mechanical reinforcement of silica aerogel. Two sustainable sol–gel based approaches are proposed for hybridization of silica with SF. Hybrids obtained by the one step sol–gel synthesis approach demonstrate better mechanical performance. Molar ratio of SF to organosilanes is the most determinant factor for resulting final properties. Both synthesis approaches led to significant reduction in the time required for preparation of strong hybrid aerogels.

Silica-based methyltrimethoxysilane (MTMS) offers unique properties as an alternative material for hydrophobic surfaces. In this study, SiO 2 obtained through the MTMS precursor with various concentrations of cetyltrimethylammonium bromide (CTAB) 0.75 wt%, 1.5 wt%, and 2.25 wt% were prepared by sol-gel method to modify and improve a hydrophobic surface. With the addition of CTAB, particle sizes are more extensive, and peak diffractions shift to a lower angle according to scanning electron microscope (SEM) images and X-ray diffraction (XRD), respectively. Fourier transform infrared (FTIR) demonstrated Si-O-Si asymmetric stretching bonds. Then, the samples were coated on steel plate substrates by the dip-coating method. Based on atomic force microscope (AFM) analysis, surface roughness was larger because of the presence of CTAB. Furthermore, water contact angle (WCA) was measured to characterize hydrophobicity using distilled, deionized, and seawater media. The WCA of the samples was more significant with the increase of CTAB content. The sample dropped to seawater medium possesses the largest WCA with a magnitude of 126.1 ± 0.8°. Because the samples with CTAB content coated on steel plate substrates own hydrophobicity, they are useful for drag reduction application on the ship’s hull coating. Graphical Abstract Schematic illustration of the coating structure and the fabricated samples with different media such as distilled, deionized, and seawater. Highlights SiO 2 -based MTMS using CTAB modifications was synthesized by the sol-gel method. Modified SiO 2 was coated on a steel plate substrate with commercial paint by the dip-coating method. The hydrophobicity of the samples was compared to the different concentrations of CTAB. The water contact angle was measured by comparing different media such as distilled, deionized, and seawater. The morphology obtained was spherical-like particles.

In the present study, a two-stage process was used to create hydrophobic and anti-fouling thin films on copper substrates. Initially, zinc oxide (ZnO) thin film was deposited on the copper substrate via a sol-gel method. Then, the film was modified with stearic acid. The structure and morphology of the thin films were characterized through X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and Fourier transform infrared (FTIR) spectroscopy. The water contact angle on the film surface was investigated by a water contact angle analyzer. Potentiodynamic polarization and salt spray tests were used to study the corrosion behavior of the copper and coated copper samples. Also, the antifouling properties of the thin films were investigated. Based on the FE-SEM result, the zinc oxide nanoparticle size was obtained as 60 nm. The water contact angle on the copper and coated copper samples increased from 39° to 155°. The corrosion current densities of the copper and coated copper samples were reduced from 1.31 μA/cm 2 to 2.7 × 10 −3  μA/cm 2 . In addition, the thin film showed the antifouling effect. Graphical abstract

Exploring novel iodine sorbent with high efficiency and low cost is a meaningful and challenging topic. Herein, a series of iodine sorbents Cu 0 @SiO 2 were firstly prepared by using SiO 2 derived from rice husks as support materials. The obtained Cu 0 @SiO 2 materials were employed to capture iodine gas. The effects of Cu content, contact time and adsorption temperature on the iodine adsorption behavior were investigated. The I 2 adsorption capacity of Cu 0 @SiO 2 reached up to 1105 mg/g with short time at 200 °C. The high chemical iodine adsorption ratio (95.11%) was achieved. Furthermore, the iodine capture mechanism for Cu 0 @SiO 2 was mainly chemical, that is formation of stable CuI by chemical reaction between Cu 0 and I 2 . The results demonstrated that Cu 0 @SiO 2 derived from rice husk was a potential promising adsorbent owing to the low cost and high capture efficiency. Graphical Abstract Novel Cu 0 @SiO 2 with high I 2 adsorption capacity and low cost was facilely fabricated using rice husk-based SiO 2 as support. I 2 adsorption capacity of Cu 0 @SiO 2 reached up to 1105 mg/g. The high chemical iodine adsorption ratio (95.11%) was achieved. Adsorption mechanism was that Cu 0 reacted with I 2 to form stable CuI. Highlights Novel Cu 0 @SiO 2 with high I 2 adsorption capacity and low cost was reported. Cu 0 @SiO 2 was facilely fabricated using rice husk-based SiO 2 as support. I 2 adsorption capacity of Cu 0 @SiO 2 reached up to 1105 mg/g. The high chemical iodine adsorption rate (95.11%) was achieved. Adsorption mechanism was that Cu 0 reacted with I 2 to form stable CuI.

Recently, there has been increasing interest in developing artificial superhydrophobic surfaces, especially in the field of self-cleaning application. However, the poor robustness and high-cost preparation of these surfaces have always been some issues for their industrial development. Herein, we describe an environmentally friendly way to prepare stable, robust, and transparent superhydrophobic coatings through the deposition of a rough substructure of TiO 2 film followed by chemical modification using octadecyltrichlorosilane (OTS), a fluorine-free organic silane. The as-prepared coatings exhibited a great superhydrophobic property and ultralow adhesion (with a static water contact angle of 158 ± 2° and sliding angle of 4 ± 1°). It was found that the superhydrophobic coatings can still maintain good performance after UV irradiation, chemical immersion, and physical abrasion. More importantly, the coated surfaces showed an excellent self-cleaning ability against dirt particles after rinsed with water droplets. Highlights Environmentally friendly and low-cost method to prepare superhydrophobic coatings using TiO 2 thin film and monolayer octadecyltrichlorosilane (OTS). High transparency of the as-prepared superhydrophobic coatings. The superhydrophobic coatings exhibited good chemical and mechanical stability. The surface of superhydrophobic glass showed an excellent self-cleaning property.

Oxygen evolution reaction (OER) during water splitting majorly based on the structure and nature of the electrocatalyst. Perovskite oxides (ABO 3 ) have a flexible structure and range of physicochemical features that make them interesting for the present study. Therefore, scientists are interested in using electrocatalyst Perovskite oxides (ABO 3 ) for OER. Nanostructures and amorphous patterns can appear when cations from the perovskite matrix are leached away from the A site. One of the most challenging problems is gaining enormous active amorphous subjects from cations in the B site rather than simply dissolving cations in the A site. In the present study, the crystalline perovskite (DyNiO 3 ) has been fabricated, which is converted into an amorphous nanostructured comparative to NiO, and characterized via numerous analytical characterization methods to investigate the structural, morphological, and textural characteristics. The designed substance is then investigated for electrochemical characterizations to evaluate the overpotential, Tafel slope, and durability. Among all, DyNiO 3 responses have a slight overpotential (η) of 265 mV and a low Tafel slope of 78 mV/dec with greater durability of 49 h. The efficient outcomes of the DyNiO 3 are because of the grater valence state of Ni 3+ containing edge splitting octahedral-frameworks, which are bordering by interstitial deformed octahedral Dy 3+ ion. This research improves perovskite oxides function as catalysts and can be applied to developing enhanced OER electrocatalysts and other energy applications in the near future. Graphical Abstract DyNiO3 was prepared and then deposited on the substrate such as nickel foam. The deposited nickel foam was then employed for the electrochemical measurements such water splitting applications. The chronoamperometric text was performed to conform the stability of the material. The material remained stable upto 84 h. Highlights The DyNiO 3 was fabricated via simple hydrothermal method. The fabricated material is characterized via numerous analytical characterization. The designed substance is then investigated for electrochemical characterizations to evaluate the overpotential, Tafel slope and durability. The DyNiO 3 responses a low overpotential of 265 mV and a low Tafel slope of 78 mV/dec with greater durability of 49 h.

Herein report, we aim to study the structural, dielectric, and magnetic properties for multifunctional perovskite materials LaCo 0.2 Mn 0.8 O 3 and La 2 CoMnO 6 nanoparticles, which were synthesized by a modified sol–gel route. Citric acid was processed as the chelating agent; gelation slurry formed by irradiation process which exposed to a total gamma radiation dose of 25 kGy at a dose rate of ~1.2 Gy/h to obtain more stability and high purity multifunctional perovskite materials. XRD notarizes the genesis of one pure phase orthorhombic perovskite structure. A full agreement between the particle sizes was investigated by HRTEM and the XRD data was observed. Raman spectra result assigned to the antisymmetric stretching mode and symmetric stretching mode of the (Co/Mn) O 6 octahedra, which related to lattice distortions. The as-prepared perovskite materials exhibit ferromagnetic nature with different values of magnetization. Electron Spin Resonance (ESR) measurements are also carried out in the LCMO multifunctional nanoparticle systems, which suggests the occurrence of Jahn–Teller glass analogous to the spin-glass behavior. The complex impedance displayed high impacts on the electrical properties. The high value of dielectric constant for LCMO prepared nanoparticle systems may be used in electric tunable devices. Highlights Novel modified sol-gel route by gamma radiation used to synthesis more stability and high purity multifunctional perovskite materials (LaCo 0.2 Mn 0.8 O 3 , and La 2 CoMnO 6 ). These multifunctional materials have orthorhombic structure lattices. LCMO multifunctional nanoparticle systems have a spin-glass behavior. The high value of dielectric constant for LCMO nanoparticle multifunctional materials is promising in electric tunable devices.

Designing luminescent nanohybrids for bioimaging proposes has been explored by different approaches in the literature. In this context, here silica luminescent nanohybrids containing Eu 3+ -complexes were synthesized in three different approaches to determine the better methodology to obtain the most efficient emissive final hybrid and its applicability in cell imaging by using the Eu 3+ luminescent probe properties. For this, the synthesized dense Stöber silica nanoparticles, SiO 2 , had their surface functionalized with APTES, in which its amine group reacted with salicylaldehyde to form a Schiff base ligand (SB), yielding the SiO 2 -SB system. Then, Eu 3+ ion was coordinated to the SB, followed by the displacement of coordinated water molecules by dibenzoylmethane (dbm), resulting in the SiO 2 -[Eu1] hybrid. SiO 2 -[Eu2] hybrid, in turn, was obtained from tris -[Eu(dbm) 3 ] complexes coordinated to the imine groups grafted on the SiO 2 -SB surface. For the third hybrid, SiO 2 -[Eu3], a new Eu 3+ -Schiff base complex displaying a triethoxysilyl group was grafted onto the SiO 2 surface. The three luminescent hybrids are spheroidal shaped with 100 nm-size and they are red emitters with long lifetime (0.34–0.61 ms) and high photostability when exposed to continuous 340 nm UV radiation. Quantum efficiency ( Q Eu Eu ) as well as the number of coordinated water molecules (q H2O ) to the Eu 3+ was estimated using the LUMPAC software package and Horrocks equation, respectively. Although the three strategies exhibited suitable photophysical results, SiO 2 -[Eu1] was classified as the best hybrid considering its higher Q Eu Eu and color purity values, and it was evaluated as non-toxic according to its bio-viability in CHO-k1 cells in different doses. Exploratory cell imaging tests using such hybrid indicated cell marking near the nucleus with the internalization of nanoparticles in the cell confirmed by Eu 3+ ( 5 D 0  →  7 F J ) narrow emission bands. Therefore, SiO 2 -[Eu1] hybrid manifested suitable shape and size, optical, and biocompatibility features that make it promising to be applied as a luminescent stain for cell imaging. Graphical abstract Left—Graph expressing the cell viability from the cytotoxicity test of CHO-k1 cells as function of concentration performed with the hybrids SiO2-[Eu1], SiO2-[Eu2], and SiO2-[Eu3], obtained from Approach 1, Approach 2, and Approach 3, respectively. Middle—Suggested final structures of complexes grafted on silica particles for the three tested approaches. Right—TEM, and Confocal images of CHO-k1 cells incubated with SiO2-[Eu1. Highlights Three different approaches were evaluated to prepair luminescent hybrids containing Eu 3+ -complexes. Three spherical 100 nm-sized hybrids with long lifetimes and emitting red were produced. Three spherical 100 nm-sized hybrids with long lifetimes and emitting red were produced.

In the recent years, many studies have been conducted to improve the properties of hybrid silane films, obtained by the sol-gel route, modified with corrosion inhibitors to improve the anti-corrosion properties. The inhibitors obtained from nature (green inhibitors) replace synthetic inhibitors and even rare earth elements (harmful to the environment). Within this approach, this work aims to evaluate the corrosion resistance of the modified TEOS/GPTMS (Tetraethyl orthosilicate/3-Glycidoxypropyltrimethoxysilane) hybrid film with the mixture of the garlic peel and cocoa shell powders as a pre-treatment of SAE (Society of Automotive Engineers) 1008 carbon steel, in which were added different proportions (1:1, 1:2, 2:1) of these mixtures powders, the best mixture ratio was Garlic 1:2 Cocoa. Corrosion resistance was evaluated using electrochemical techniques such as open circuit potential, electrochemical impedance spectroscopy, linear polarization resistance and Tafel polarization curves, in 0.1 mol L −1 NaCl solution. In addition to the scanning vibrating electrode technique, in 0.01 mol L −1 NaCl solution. Film morphology and elements analyses were evaluated by scanning electron microscopy with energy-dispersive spectroscopy. The chemical characterization of the film was obtained by Fourier transform infrared spectroscopy. Physical properties were analyzed by the techniques of contact angle, roughness profile and dry layer thickness. The results of the different techniques indicate that the film modified with the mixture of natural inhibitors has improved anti-corrosive properties compared to the film without natural green inhibitors. Graphical Abstract The first image entitled “Garlic peel powder ( Allium sativum L .) and Cocoa shell powder ( Theobroma Cacao )” shows garlic peel powder ( Allium sativum L .) and cocoa shell powder ( Theobroma Cacao ), both natural inhibitors used in the research, below this first image called “Clean Sample”, is SAE 1008 carbon steel after cleaning the metal surface. The image called “Film solution TEOS/GPTMS with Garlic and Cocoa” is an example of how carbon steel was immersed in the TEOS/GPTMS solution with the inhibitors mixed in different proportions. The image called “Coated steel after curing in a preheater” shows an example of how the sample looked after being cured in a preheated oven, after which they were ready to be evaluated by different techniques. The “Fourier transform infrared spectroscopy (FTIR)” image shows the results of FTIR analysis on the samples. In the image “Scanning electron vibrating technique (SVET)”, it shows the results of the SVET analyzes on the samples. The “Electrochemical Impedance Spectroscopy (EIS)” image shows the results of EIS analyzes on samples. The image “Scanning Electron Microscopy (SEM) with Energy-Dispersive Spectroscopy (EDS)” shows the results of SEM/EDS analysis on the samples. Highlights Sol–gel route modified with inhibitors to improve anticorrosion performance. EIS diagrams proved that the green inhibitors increase the film resistance. Tafel curves showed inhibitors-silane film presented higher corrosion potential. The film modified with mixture of natural inhibitor has anticorrosive properties.