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Thermoelectrics is an emerging technology in the field of renewable energy sources, and the exploration of doped materials has opened up new avenues for enhancing their performance. La-doped thermoelectric materials with the composition Bi2−xLaxTe3 (x = 0.0, 0.1, 0.2, 0.3, 0.4) were synthesized using the WOWS sol–gel method and sintered at 500 °C for 5 h. X-ray diffraction analysis confirmed a rhombohedral crystal structure with lattice constants of a = b = 4.41(2) Å and c = 29.81(3) Å. Scanning electron microscopy revealed particle-like shapes (0.7–2.5 μm). Fourier transform infrared spectroscopy confirmed the single-phase nature of the samples. DC electrical measurements showed increasing conductivity with temperature. AC electrical analysis demonstrated frequency-dependent behavior with increasing AC conductivity and decreasing loss factor and dielectric constants. Seebeck coefficient measurements exhibited temperature-dependent behavior. Thermal transport properties showed increasing thermal conductivity and volumetric specific heat with temperature, while thermal diffusivity decreased. The composition Bi1.9La0.1Te3 with x = 0.1 doping displayed lower thermal conductivity, higher electrical conductivity, and a higher ZT value, making it more suitable for thermoelectric applications. Furthermore, the sample Bi1.8La0.2Te3 exhibited favorable characteristics for energy storage applications compared to the other samples. These findings provide insights into the potential applications of La-doped bismuth telluride compounds in thermoelectric and energy storage systems. [ABSTRACT FROM AUTHOR]

In this study, pH-sensitive hydroxyapatite particles loaded with tannic acid were incorporated in polyolefin-based coatings for the corrosion protection of carbon steel. Transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA) were used to characterize the hydroxyapatite particles loaded with tannic acid (Tannic-HAP). Electrochemical impedance spectroscopy (EIS) was employed to study the protective performance of the reference and modified polyolefin coatings. The results suggest that modified coatings showed improved corrosion performance compared to the unmodified coatings. The combination of tannic acid and hydroxyapatite contributed to a more effective protection of coated carbon steel. [ABSTRACT FROM AUTHOR]

Dodecylbenzenesulfonic acid (DBSA) doped polyaniline and carbon black (CB) composites (PANI-DBSA/CB) were synthesized by in-situ polymerization of aniline in the aqueous dispersion of carbon black (CB) in the presence of ammonium persulfate (APS) as an oxidant. Various composite samples with varying amounts of CB (1 wt% and 2 wt%) were synthesized and were characterized by using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). XRD studies confirmed the formation of the well-organized and semi-crystalline structure of the composites. SEM analysis revealed the increase in grain size and the granular structure of the synthesized composites. DC conductivity was measured in the temperature range from 300 K to 393 K using two probe methods. An increase in DC conductivity was found on the inclusion of carbon black at all temperatures and the most probable model of charge transport was found to be three-dimensional variable range hopping (3D-VRH). As the concentration of CB in the composites increased, activation energy was found to be decreased. The density of states, hopping length, and hopping energy were calculated, respectively, and were found to be influenced by CB incorporation. [ABSTRACT FROM AUTHOR]

Intercalated and exfoliated nanocomposites of insulating polymers poly methyl methacrylate and acrylonitrile butadiene styrene with organically modified montmorillonite (OMMT) was prepared by solution casting method. Formation of polymer nanocomposites was confirmed by X-Ray Diffraction. Fourier transform infrared spectroscopy confirmed the interaction between polymers and cations on the surface of OMMT layers. Dielectric properties of these nanocomposites were examined at room temperature in the frequency range of 100 Hz–1 MHz. The findings of dielectric measurements exhibited higher real and imaginary dielectric permittivity values for exfoliated nanocomposites and lesser real and imaginary dielectric permittivity values for intercalated nanocomposites as compared with pure polymers in the same frequency range. The increase in the permittivity values is attributed to Maxwell Wagner polarization in exfoliated nanocomposites because of increased interfacial area between polymer and the clay layers. Decrease in dielectric permittivity in intercalated polymer nanocomposites is attributed to restricted mobility of polymer chains due to nanoscopic confinement of the polymer with the silicate layers. [ABSTRACT FROM AUTHOR]

Silica‐polyurea/polyuretane hybrid shell microcapsules (MCs) loaded with isophorone diisocyanate (IPDI) with long shelf‐life and high thermal and chemical stability are prepared via emulsification followed by interfacial polymerization at the surface of oil droplets of the oil‐in‐water emulsion. The resultant MCs are aimed at self‐healing performance in epoxy coatings. A commercially available, highly reactive polyisocyanate named tris(p‐isocyanatophenyl) thiophosphate is successfully employed as shell forming agent, while triethoxyoctylsilane and hexadecyltrimethoxysilane (HDMS) are tested as "latent" active hydrogen sources. The resulting MCs display core–shell morphology, spherical shape with diameter of 5–20 μm, shell thickness ca. 1–2 μm, and an IPDI core fraction of 69 and 65 wt %, when HDMS and triethoxyoctylsilane are employed, respectively. MCs exhibit an increased thermal stability, comparing with pure IPDI, which makes them robust enough to resist the thermal cycles involved in the coating's preparation. Stability of MCs inside specific solvents and chemicals, their chemical composition and shelf‐life as well as effect of MCs on the epoxy curing are evaluated by Fourier transformed infrared spectroscopy. MCs, remarkably, show excellent environment stability and a long shelf‐life of more than 3.5 months. Their addition to an epoxy formulation is found to heal damaged zones in the epoxy coating, as shown by scanning electron microscopy and electrochemical impedance spectroscopy. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48751. [ABSTRACT FROM AUTHOR]

In the present work, the effect of neodymium on the barium-based spinel ferrites has been investigated. A series of spinel ferrites with compositions BaNdyFe2-yO4 (y = 0.00, 0.02, 0.04, 0.06, 0.08, 0.10) was synthesized by the sol–gel technique. These spinel ferrites were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), electrical properties, and magnetic properties. X-ray analysis ascertained the formation of single-phase cubic spinel structure for all samples, while some traces of second phase recognized as orthorhombic phase NdrFeO3 in the last two samples. There was an overall increase in the lattice parameter as neodymium (Nd) contents were substituted. There was a regular increase in bulk density and X-ray density with the increase in neodymium concentration. Electrical measurements demonstrate that resistivity and activation energy increase with the neodymium substitution, while dc resistivity decreases with the rise of temperature showing the semiconductor nature of the synthesized ferrites. Curie temperature dropped with the substitution of neodymium concentration. Magnetic properties of the synthesized materials were studied between applied magnetic field range − 2 KOe and + 2 KOe and corresponding M–H loops were obtained. The saturation magnetization and remanence decreased on the substitution of Nd while coercivity (Hc) values enhanced. The smaller values of anisotropic constant exhibited the isotropic nature of these ferrites. The prepared spinel ferrites might be suitable for high-frequency multilayer chip inductors. [ABSTRACT FROM AUTHOR]

V2O3 samples were successfully prepared using [VOSO4·xH2O] as the starting material by a template-free hydrothermal method with the addition of KBrO3. The prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and cyclic voltammetry (CV). The XRD result shows the rhombohedral structure for V2O3 with an average crystallite size in the range of 22 nm. With the increase in reaction time (6-8 h), the morphology of the samples changes from nano-flower to nano-ribbons as indicated by SEM micrographs. FTIR spectrum shows that the band at 1286 cm−1, related to C-OH stretching and OH bending vibrations and indicate the presence of residual hydroxyl groups. The electrochemical measurements show an excellent storage response, kinetics and reversibility of the electrode material. Further, good rate capability of the materials was also observed. [ABSTRACT FROM AUTHOR]

Dielectric constant ɛ′ and loss factor ɛ″ were measured in intercalated polypyrrole/aluminum pillared montmorillonite (PPy/Al-PMMT) clay nanocomposites in the frequency range 100 Hz to 1 MHz. The PPy/Al-PMMT nanocomposites were prepared by in situ polymerization of pyrrole in aqueous dispersion of varying amounts of (Al-PMMT) clay from 0.2 to 10%, using FeCl · 6HO as an oxidant. Formation of the nanocomposite was studied by FTIR and intercalation of PPy in the clay galleries was confirmed by XRD. The nanocomposites exhibited very large values of ɛ′ and ɛ″ at low frequency which decreased with frequency and increased with the clay content in the samples. Electric modulus formalism exhibited a peak in the frequency dependence curves of imaginary part of the electric modulus due to conductivity relaxation process. The peak of conductivity relaxation shifted towards higher frequencies and the magnitude of relaxation decreased with the increase of MMT content in the composites. [ABSTRACT FROM AUTHOR]