In this work, new films containing composite materials based on blends of thermoplastic polymers of the polyurethane (TPU) and polyolefin (TPO) type, in the absence and presence of BaTiO₃ nanoparticles (NPs) with the size smaller 100 nm, were prepared. The vibrational properties of the free films depending on the weight ratio of the two thermoplastic polymers were studied. Our results demonstrate that these films are optically active, with strong, broad, and adjustable photoluminescence by varying the amount of TPU. The crystalline structure of BaTiO₃ and the influence of thermoplastic polymers on the crystallization process of these inorganic NPs were determined by X-ray diffraction (XRD) studies. The vibrational changes induced in the thermoplastic polymer’s matrix of the BaTiO₃ NPs were showcased by Raman scattering and FTIR spectroscopy. The incorporation of BaTiO₃ NPs in the matrix of thermoplastic elastomers revealed the shift dependence of the photoluminescence (PL) band depending on the BaTiO₃ NP concentration, which was capable of covering a wide visible spectral range. The dependencies of the dielectric relaxation phenomena with the weight of BaTiO₃ NPs in thermoplastic polymers blends were also demonstrated.

In this work, a complementary ultraviolet-visible (UV-VIS) spectroscopy and photoluminescence (PL) study on melatonin (MEL) hydrolysis in the presence of alkaline aqueous solutions and the photodegradation of MEL is reported. The UV-VIS spectrum of MEL is characterized by an absorption band with a peak at 278 nm. This peak shifts to 272 nm simultaneously with an increase in the band absorbance at 329 nm in the presence of an NaOH solution. The isosbestic point localized at 308 nm indicates the generation of some chemical compounds in addition to MEL and NaOH. The MEL PL spectrum is characterized by a band at 365 nm. There is a gradual decrease in the MEL PL intensity as the alkaline solution concentration added at the drug solution is increased. In the case of the MEL samples interacting with an alkaline solution, a new photoluminescence excitation (PLE) band at 335 nm appears when the exposure time to UV light reaches 310 min. A down-shift in the MEL PLE band, from 321 to 311 nm, as a consequence of the presence of excipients, is also shown. These changes are explained in reference to the MEL hydrolytic products.

Fabrication aspects of PdO thin films and coatings are reviewed here. The work provides and organizes the up-to-date information on the methods to obtain the films. In recent years, the interest in Pd oxide for different applications has increased. Since Pd can be converted into PdO, it is instructive to pay attention to the preparation of the pure and the alloyed Pd films, heterostructures, and nanoparticles synthesized on different substrates. The development of PdO films is presented from the early reports on coatings’ formation by oxidation of Pd foils and wires to present technologies. Modern synthesis/growth routes are gathered into chemical and physical categories. Chemical methods include hydrothermal, electrochemical, electroless deposition, and coating methods, such as impregnation, precipitation, screen printing, ink jet printing, spin or dip coating, chemical vapor deposition (CVD), and atomic layer deposition (ALD), while the physical ones include sputtering and cathodic arc deposition, laser ablation, ion or electron beam-induced deposition, evaporation, and supersonic cluster beam deposition. Analysis of publications indicates that many as-deposited Pd or Pd-oxide films are granular, with a high variety of morphologies and properties targeting very different applications, and they are grown on different substrates. We note that a comparative assessment of the challenges and quality among different films for a specific application is generally missing and, in some cases, it is difficult to make a distinction between a film and a randomly oriented, powder-like (granular), thin compact material. Textured or epitaxial films of Pd or PdO are rare and, if orientation is observed, in most cases, it is obtained accidentally. Some practical details and challenges of Pd oxidation toward PdO and some specific issues concerning application of films are also presented.

This article’s objective is the synthesis of new composites based on thermoplastic polyurethane (TPU) and TiO₂ nanowires (NWs) as free-standing films, highlighting their structural and optical properties. The free-standing TPU–TiO₂ NW films were prepared by a wet chemical method accompanied by a thermal treatment at 100 °C for 1 h, followed by air-drying for 2 h. X-ray diffraction (XRD) studies indicated that the starting commercial TiO₂ NW sample contains TiO₂ tetragonal anatase (A), cubic Ti_0.91O (C), and orthorhombic Ti₂O₃ (OR), as well as monoclinic H₂Ti₃O₇ (M). In the presence of TPU, an increase in the ratio between the intensities of the diffraction peaks at 43.4° and 48° belonging to the C and A phases of titanium dioxide, respectively, is reported. The increase in the intensity of the peak at 43.4° is explained to be a consequence of the interaction of TiO₂ NWs with PTU, which occurs when the formation of suboxides takes place. The variation in the ratio of the absorbance of the IR bands peaked at 765–771 cm⁻¹ and 3304–3315 cm⁻¹ from 4.68 to 4.21 and 3.83 for TPU and the TPU–TiO₂ NW composites, respectively, with TiO₂ NW concentration equal to 2 wt.% and 17 wt.%, indicated a decrease in the higher-order aggregates of TPU with a simultaneous increase in the hydrogen bonds established between the amide groups of TPU and the oxygen atoms of TiO₂ NWs. The decrease in the ratio of the intensity of the Raman lines peaked at 658 cm⁻¹ and 635 cm⁻¹, which were assigned to the vibrational modes E_g in TiO₂ A and E_g in H₂Ti₃O₇ (I_TiO2-A/I_H2Ti3O7), respectively, from 3.45 in TiO₂ NWs to 0.94–0.96 in the TPU–TiO₂ NW composites, which indicates that the adsorption of TPU onto TiO₂ NWs involves an exchange reaction of TPU in the presence of TiO₂ NWs, followed by the formation of new hydrogen bonds between the -NH- of the amide group and the oxygen atoms of Ti_xO_2x-mn, Ti₂O₃, and Ti_0.91O. Photoluminescence (PL) studies highlighted a gradual decrease in the intensity of the TPU emission band, which is situated in the spectral range 380–650 nm, in the presence of TiO₂ NW. After increasing the TiO₂ NW concentration in the TPU–TiO₂ NW composite mass from 0 wt.% to 2 wt.% and 17 wt.%, respectively, a change in the binding angle of the TPU onto the TiO₂ NW surface from 12.6° to 32° and 45.9°, respectively, took place.