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.

This paper prepared composites under the free membranes form that are based on thermoplastic polymers of the type of polyurethane (TPU) and polyolefin (TPO), which are blended in the weight ratio of 2:1, and ceramic nanoparticles (CNs) such as BaSrTiO₃ and SrTiO₃. The structural, optical, and conductive properties of these new composite materials are reported. The X-ray diffraction studies highlight a cubic crystalline structure of these CNs. The main variations in the vibrational properties of the TPU:TPO blend induced by CNs consist of the following: (i) the increase in the intensity of the Raman line of 1616 cm⁻¹; (ii) the down-shift of the IR band from 800 to 791 cm⁻¹; (iii) the change of the ratio between the absorbance of IR bands localized in the spectral range 950–1200 cm⁻¹; and (iv) the decrease in the absorbance of the IR band from 1221 cm⁻¹. All these variations were correlated with a preferential adsorption of thermoplastic polymers on the CNs surface. A photoluminescence (PL) quenching process of thermoplastic polymers is demonstrated to occur in the presence of CNs. The anisotropic PL measurements have highlighted a change in the angle of the binding of the TPU:TPO blend, which varies from 23.7° to ≈49.3° and ≈53.4°, when the concentration of BaSrTiO₃ and SrTiO₃ CNs, respectively, is changed from 0 to 25 wt. %. Using dielectric spectroscopy, two mechanisms are invoked to take place in the case of the composites based on TPU:TPO blends and CNs, i.e., one regarding the type of the electrical conduction and another specifying the dielectric–dipolar relaxation processes.

Nanocomposites based on Fe₃O₄ and carbonaceous nanoparticles (CNPs), including carbon nanotubes (CNTs) and graphene derivatives (graphene oxide (GO) and reduced graphene oxide (RGO)), such as Fe₃O₄@GO, Fe₃O₄@RGO, and Fe₃O₄@CNT, have demonstrated considerable potential in a number of health applications, including tissue regeneration and innovative cancer treatments such as hyperthermia (HT). This is due to their ability to transport drugs and generate localized heat under the influence of an alternating magnetic field on Fe₃O₄. Despite the promising potential of CNTs and graphene derivatives as drug delivery systems, their use in biological applications is hindered by challenges related to dispersion in physiological media and particle agglomeration. Hence, a solid foundation has been established for the integration of various synthesis techniques for these nanocomposites, with the wet co-precipitation method being the most prevalent. Moreover, the dimensions and morphology of the composite nanoparticles are directly correlated with the value of magnetic saturation, thus influencing the efficiency of the composite in drug delivery and other significant biomedical applications. The current demand for this type of material is related to the loading of a larger quantity of drugs within the hybrid structure of the carrier, with the objective of releasing this amount into the tumor cells. A second demand refers to the biocompatibility of the drug carrier and its capacity to permeate cell membranes, as well as the processes occurring within the drug carriers. The main objective of this paper is to review the synthesis methods used to prepare hybrids based on Fe₃O₄ and CNPs, such as GO, RGO, and CNTs, and to examinate their role in the formation of hybrid nanoparticles and the correlation between their morphology, the dimensions, and optical/magnetic properties.

Mixtures of nitrogen-doped titanium dioxide (TiO ₂ :N) with different concentrations of Ag and/or SiO ₂ particles (0.5, 1 and 2 wt.%) were prepared in solid state by mechanico-chemical interactions. Using UV–VIS spectroscopy, Raman scattering, photoluminescence (PL) and photoluminescence excitation (PLE), the influence of the particles on the host material is evaluated. UV–VIS spectroscopy studies indicate a TiO ₂ :N band gap shift to the UV range with increasing concentrations of SiO ₂ and Ag particles. PL intensities decrease with increasing concentrations of Ag and/or SiO ₂ particles in the TiO ₂ :N host matrix, which in turn could effectively restrict the electron and hole recombination. To explain these processes, the different de-excitation ways will be advanced, taking into account the energy levels diagram of TiO ₂ :N/Ag, TiO ₂ :N/SiO ₂ and TiO ₂ :N/Ag/SiO ₂ systems. PLE spectra show a gradual decrease in their relative intensities after 165 min of continuous irradiation due to photosensitivity of TiO ₂ :N. The plasmonic effect of Ag particles in the TiO ₂ :N/Ag system is highlighted for the first time by PLE studies.

The exciton–phonon interaction, considered as a stimulated Raman scattering process, is studied in different semiconductor mixtures: PbI ₂ /TiO ₂ , PbI ₂ /Si and CdS/Si. Raman spectra recorded at excitation wavelengths of 514.5 and 488 nm for PbI ₂ and CdS, respectively, reveal a strong enhancement of the Raman lines peaked at 97 and 305 cm ⁻¹ , evaluated by the ratio I _TK / I _{300 K} between the relative intensities of the spectra recorded in the temperature range of 88–300 K. It is found that PbI ₂ and CdS exhibit a decrease in the Raman intensity modes with decreasing temperature, while in TiO ₂ and Si an increase in the Raman lines intensities peaked at 138 and 520 cm ⁻¹ is observed. This behavior can be explained by an energy transfer process from PbI ₂ or CdS towards TiO ₂ and Si. This explanation is supported by the schematic potential energy levels diagram obtained from the density of states, which is calculated using the density functional theory. According to this energy levels diagram, the electrons are expected to migrate directly from the conduction band (CB) energetic levels of the PbI ₂ and CdS towards the CB levels of TiO ₂ and Si.