Perovskite barium titanate (BaTiO₃) multipods were prepared via high temperature solid state reaction. The crystal structure and morphology of BaTiO₃ particles were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), and scanning probe microscopy (SPM). The XRD analysis of the crystal structure revealed that a single-phase compound was formed having tetragonal crystal structure. Calorimetric study (DSC) over room to high temperature was used to find the energy involved in different steps of synthesis especially during the initiation and the termination process for the formation of BaTiO₃. These multipods have high average aspect ratio (∼10, where average diameter ∼300 nm and average length ∼3 μm) as seen from FESEM. UV-Vis spectroscopy reveals that the prepared material is UV active. The bulk and surface chemical composition of these BaTiO₃ particles as investigated by Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) spectra reveals that in the prepared BaTiO₃, the titanium ions exist in two different oxidation states, namely Ti³⁺ and Ti⁴⁺. The BaTiO₃ multipod exhibits high permittivity with relatively low dielectric loss. From impedance analysis of the material, the dual resistivity characteristics, one for grain and the other for grain-boundary can be distinguished. An equivalent circuit has been proposed through analysis of the complex impedance plot (Nyquist plot) for BaTiO₃ multipods. This material has perfect capacitative nature as seen from the Bode plot, and can be used for charge storage devices and other electronic applications. From temperature dependent dielectric analysis, the Curie temperature of BaTiO₃ multipods is found to be ∼85 °C.

In this study, mesoporous silica encapsulated with magnetic MnFe₂O₄ nanoparticles is synthesized by a solvothermal method. The synthetic route is feasible and widely applicable. The obtained products have been characterized by an X-ray powder diffraction (XRD) pattern, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high-resolution TEM (HRTEM) and nitrogen adsorption–desorption isotherm measurements. The synthesized magnetic mesoporous MnFe₂O₄ nanoparticles are monodispersed with a mean diameter of 200 nm, and have an obvious mesoporous silica shell of ∼20 nm. The surface area of magnetic mesoporous MnFe₂O₄ nanocomposites is 423 m² g⁻¹. The nanoparticles are superparamagnetic in nature at room temperature and can be separated by an external magnetic field. This magnetic mesoporous material is used as a catalyst for the degradation of methyl orange dye. The merits of the effect under different conditions like pH, temperature, light and sonolysis have been evaluated by investigating the degradation of azo dye. The mesoporous MnFe₂O₄ nanocomposites have effective adsorption of dyes inside the porous network followed by degradation with the central magnetite core and regeneration of the catalyst with the help of a simple magnet for successive uses.

Flexible polyurethane (PU)–titania nanocomposites of different compositions are prepared by a melt-mixing technique. Two different sequences of mixing method are adapted to prepare two different sets of composites. All these composites show composition-dependent dielectric properties, and composites with tunable dielectric properties can be obtained through judicial adjustment of composition. The morphology of these composites has been investigated by field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), and scanning probe microscopy (SPM). Dielectric properties at low frequency regions are found to depend on morphology. These composites show excellent piezoelectric behaviour, where the dielectric constant and conductivity of these flexible composites change appreciably with changes in applied stress. The dielectric breakdown strength of these composite is also measured. To understand the thermal stability of these composites, thermogravimetric analysis has been applied and it was found that a composite containing 12.49 vol% titania shows higher thermal stability, beyond which, stability decreases due to the photocatalytic effect of titania.