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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, new optical properties of composites based on polystyrene (PS) microspheres and graphene oxide (GO) are reported. The radical polymerization of styrene in the presence of benzoyl peroxide, pentane and GO induces the appearance of new ester groups in the PS macromolecular chains remarked through an increase in the absorbance of the infrared (IR) band at 1743 cm−1. The decrease in the GO concentration in the PS/GO composites mass from 5 wt.% to 0.5 wt.% induces a diminution in the intensities of the D and G Raman bands of GO simultaneous with a down-shift of the D band from 1351 to 1322 cm−1. These variations correlated with the covalent functionalization of the GO layers with PS. For the first time, the photoluminescent (PL) properties of PS/GO composites are reported. The PS microspheres are characterized by a PL band at 397 nm. Through increasing the GO sheets’ concentration in the PS/GO composite mass from 0.5 wt.% to 5 wt.%, a PS PL quenching process is reported. In addition, in the presence of ultraviolet A (UVA) light, a photo-degradation process of the PS/GO composite having the GO concentration equal to 5 wt.% is demonstrated by the PL studies.

The effect of UV light on the cationic photopolymerization of the SU8 negative photoresist is shown by photoluminescence (PL) studies. Our results demonstrate that the cationic photopolymerization reaction of the SU8 photoresist takes place predominantly under the influence of the UVA light. Using UVA light, the influence of carbon nanotubes [of the types single-walled carbon nanotubes (SWNTs), double-walled carbon nanotubes (DWNTs), multiwalled carbon nanotubes (MWNTs), and SWNTs functionalized with carboxyl groups (SWNTs-COOH)] on the cationic photopolymerization process of the SU8 photoresist is shown by PL studies. The cationic photopolymerization of the SU8 photoresist is monitored by the variations of the two emission bands with maxima at ∼400−429 nm and 523−556 nm. The increase in the relative intensity of the PL band at ∼523− 556 nm is dependent on (i) the carbon nanotube concentration in the SU8 photoresist matrix; (ii) the type of carbon nanotubes, i.e., SWNTs, DWNTs, and MWNTs; and (iii) the nonfunctionalized and functionalized state of SWNTs. The results reported in this work demonstrate that PL can be used as a complementary method to Raman scattering and IR spectroscopy in the investigation of the cationic photopolymerization reaction of the SU8 negative photoresist. A decrease in the wrapping angle of carbon nanotubes with the SU8 photoresist is highlighted by anisotropic PL studies.