No abstract

Synthesis of polymeric blends and nanocomposites of tuned properties gained increasing attention worldwide. In the present report, semicrystalline PVA/PEO blend films loaded with clay nanoparticles (Nps), at doping ratios in the range 3-12 wt%, were prepared and characterized by various techniques. XRD, SEM, and FTIR were used for probing the semicrystalline nature, morphology, and microstructure of the blend and complexation between its constituents. UV-vis-IR spectroscopy was performed to study the optical properties and optical constants of the prepared nanocomposites. Moreover, the dielectric properties were studied in the frequency range 0.1 Hz to 20 MHz and at different temperatures. Clay Nps incorporation decreased the blend crystallinity and affect its surface morphology without changing the blend structure. Strong interaction and complexation between the films' constituents are noted through the change in XRD peaks position and FTIR band intensity. The values of optical transmittance and absorption index of the films as well as the bandgap (E g ), refractive index (n), and optical dispersion parameters depend mainly on the clay Nps doped ratio. The direct E g decreased from 4.5 to 3.9 eV and n increased from 3.28 to 4.78. The dielectric constant, dielectric loss tangent, dielectric moduli (M′, M″), and ac conductivity were improved with the clay Nps content and also influenced by the temperature. The nature of the relaxation peaks in tan (δ) and M″ indicate the deviation of the conduction process from the ideal Debye type behavior. Increasing the semiconducting nature and the value of ac conductivity encourage the utilization of these nanocomposites in various electric and optoelectric applications.

Solid-polymer electrolytes (SPE) based on rare-earth doping is a growing approach for the development of various optoelectronic and ion-conducting devices. Eu3+/PEO–PVA SPE was prepared by solution casting. The impacts of Eu3+ content on the microstructure, chemical composition, and complexation with the functional groups of the blend as well as on the film morphology were evaluated by X-ray diffraction, FT-IR spectroscopy, and FE-SEM microscopy. It was revealed that the film's crystallinity and optical transmittance can be tailored by Eu3+ content. Tauc's method illustrated that the films exhibit dual band gaps on both the low energy side (2.0–2.8 eV) and the high energy side (4.0–4.38 eV). In addition, the refractive index and optical conductivity of SPE were greatly enhanced with increasing Eu3+ content. The current–voltage characteristic curves were recorded at an applied voltage range of 0–10 V, and temperature range of 30–100 °C. The materials exhibited non-Ohmic behavior. The DC conductivity ($${\sigma }_{\mathrm{dc}})$$ σ dc ) values of the pure and 6 wt% Eu3+-doped blend were in the range of 1.16 × 10–6–2.05 × 10–6 S/cm and 1.73 × 10–6–3.36 × 10–6 S/cm, respectively. The relations between the current density and the electric field revealed that the Schottky emission is the most suitable conduction mechanism. The results indicate that Eu3+/PEO–PVA SPE is suitable for some optoelectronic applications and ion-conducting devices.

Nanocomposites with thermal stability and tunable optical properties became essential for developed optoelectronic and electrochemical devices. This work represents an attempt to synthesize PVA–PEO polymeric blend and modifies its structural, optical, and thermal properties. This was performed by incorporating different ratios of double-layered hydroxide (Zn/Fe-LDH) nanoplates (NP) which were prepared by the co-precipitation process. XRD results revealed that the incorporation of LDH, 43 nm in size and rhombohedral phase, influenced the degree of crystallinity (X C) of the blend. FE-SEM analysis showed the uniform distribution of LDH NP in the polymer matrix until 7.0 wt% content, beyond this ratio some voids were formed in the blend surface and particle agglomeration took place. FTIR spectroscopy illustrated the good miscibility of the polymers forming the blend, the interaction, and complexation between LDH NP and the blend functional groups. UV–vis-NIR spectroscopy analysis was performed to study the transmittance of the nanocomposites, extinction coefficient, refractive index, and optical conductivity. Besides, the direct and indirect band gaps of the films were found to decrease with increasing LDH NP content until a certain limit, after which they increased again. TGA&DSC analysis revealed the thermal stability of the films until 240 °C, and the DSC curves indicated three endothermic peaks. The obtained results confirmed that LDH NP incorporation is an interesting approach for tuning the optical and thermal properties to widen the technological applications based on PVA–PEO blend.

The variation in the modes of a new ruthenium diphenyl carbazide complex (RuDPC) during changing of ruthenium (Ru) concentration within 0.01 ≤ X ≤ 0.09 in diphenyl carbazide (DPC) are investigated using IR analysis. Variation in some IR spectroscopic parameters during the increase of Ru content in pure DPC has been recorded. The variation in both the relaxation time and the rotational energy barrier for RuDPC samples at the mode 505 cm-1 supports a change that occurs at X ≈ 0.05. Micro-structure of RuDPC samples was studied by X-ray analysis and scanning electron microscopy. Moreover, SEM pictures and EDAX measurements were made revealing the strong Ru-signals indicating the presence of Ru and their distributions in the DPC matrix. Also results indicated that Ru inclusion in DPC matrix changes its morphology with a uniform distribution of Ru. Besides, X-ray diffraction patterns revealed RuDPC samples are represented by a mixture of amorphous and crystalline structure, wherever the phase-nature crystallization of RuDPC samples reinforced when the concentration of Ru is augmented. The crystal structure is changed to tetragonal structure after addition of ruthenium metal to pure orthorhombic DPC matrix. The spectroscopic properties of RuDPC complex is seemed to be dependent on its characteristics to the effect of radiation (FTIR), as a solar material in the application of this field; due to DPC is a photosensitive material, so that there are a number of optical applications which depend upon optically induced structure transition energy states for the complex.