Structural, thermal, and linear optical properties of SiO 2 nanoparticles dispersed in polyvinyl alcohol nanocomposite films (original) (raw)
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2021
In the present work, gallium oxide nanoparticles (nGa2O3) are synthesized via the thermal microwave combustion method, while nanocomposites of polyvinyl alcohol (PVA) polymer with various concentrations of nGa2O3 (0, 1, 2, 3, 4, and 5 wt%) are prepared by the casting technique. The structural characterization of nGa2O3, PVA, and films of PVA-Ga2O3 nanocomposites are studied using X-ray diffraction (XRD), High-resolution transmission electron microscopy (HRTEM), and Fourier-transform infrared spectroscopy. The HRTEM and XRD examinations showed that the prepared nGa2O3 has an average crystallite size of ~ 5.6 nm and particle size of ~ 0.9 µm. On another side, the optical transmission spectra were performed in the spectral range 250 to 2500 nm at room temperature. The refractive index, absorption coefficient, and optical bandgap (Eg) were determined using the Wemple-DiDomenico single oscillator model. It was shown that Eg slightly reduced from 3.61 to 3.55 eV with increasing the Ga2O3 ...
Journal of Materials Science: Materials in Electronics, 2022
The present study aims to prepare a low-cost, eco-friendly, free-standing film with optimized physical properties. A PVA composite of hard-soft hybrid filler ratio 1:3 (nSiO 2 :Gl) is prepared by casting. Dynamic mechanical analyses are processed in the frequency range (0.01-9 Hz). Moreover, dielectric studies are performed in the frequency range (50 Hz-5 MHz). Herein, the modified Jonscher equation and electric modulus formalism are used to explain the results. Transmittance and reflectance of studied samples are measured in the UV-Vis range (200-700 nm). Detailed discussions of band structure, refractive index, and optoelectronic parameters are addressed. Remarkably, the results showed that mechanical and electrical properties of PVA can be tuned by careful modulation of glycerol content, whereas optical properties are more sensitive to nSiO 2 content. Finally, FTIR and SEM structural analyses investigate the induced structural changes in PVA.
The effect of silver nanoparticles doped in PVA on the structural and optical properties of composite films is studied experimentally. Samples are PVA films of 0.14 mm thickness doped with different sizes and concentrations of silver nanoparticles. Structural properties are studied using X-ray diffraction and FTIR spectrum. Using the reflectance and transmittance of samples, the effect of doped nanoparticles and their concentration on optical parameters of PVA films include absorption coefficient, optical bandgap energy, complex refractive index, complex dielectric function, complex optical conductivity, and relaxation time is extracted and discussed. The dispersion of the refractive index of films in terms of the single oscillator Wemple-DiDomenico (WD) model is investigated and the dispersion parameters are calculated. Results show that by doping silver nanoparticles in PVA, number of Bragg's planes in the structure of polymer and its crystallinity are increased noticeably. Ag-O bonds are formed in the films and the bandgap energy of samples is decreased. Calculations based on WD model confirm that by doping nanoparticles, the anion strength of PVA as a dielectric medium is decreased.
Physical Properties of Polyacrylamide/Polyvinylalcohol Silica Nanocomposites
Journal of Research Updates in Polymer Science, 2016
In this paper, samples of Polyacrylamide (PAAm) nanosilica nanocomposites were prepared having different concentration of nanosilica (0.125, 0.25, and 0.5). Polyacrylamide (PAAm) and poly (vinyl alcohol) (PVA) were blended with different ratio (3/1, 1/1, 1/3) using solution-cast technique. The prepared films were characterized by Fourier transform infrared (FTIR), X-ray diffractions (XRD) and scanning electron microscopy (SEM). FTIR spectra showed the presence of hydrogen bonding between-CONH2 groups in PAAm and-OH group in PVA and confirm the hydrophilic nature of the blends. X-ray diffractions shows the presence of a strong broad peak centered at 22º (2) confirms the amorphous nature of silica which is supposed to be the characteristic of SiO2. The results obtained from different experimental techniques were supported by SEM image analysis. The thermal stability of the nanocomposites enhanced by increasing the silica content in the blend. The DC electrical conductivity was studied for all prepared samples. It was found that the conductivity increase by increasing silica content as well as, increased by increasing the wt% of PVA.
Results in Physics, 2020
Doped polymeric hybrid thin films based on Poly-Methyl-Meth-Acrylate (PMMA) and Poly-vinyl-alcohol (PVA) doped with silica nanoparticles (SiO 2 NPs) are synthesized using the dip-coating technique. The as-prepared (PMMA-PVA)/SiO 2 nanocomposite (wt% of SiO 2 NPs = 2%, 4%, 8%, and 16%) are deposited on glass substrates. Transmittance (T%) and reflectance (R%) are measured using a UV-Vis spectrometer. Furthermore, other related optical parameters such as absorption coefficient (α), optical constants (n and k), and optical dielectric functions (ε 1 and ε 2) are calculated using experimental transmittance, reflectance spectra and well-established classical models such as Tauc, Urbach and Spitzer-Fan and Drude models. The Tauc model is used to estimate the optical bandgap energy. Incorporation of specific concentrations of SiO 2 NPs into PMMA-PVA polymeric matrix leads to a noticeable decrease of the optical bandgap. The optical bandgap of un-doped PMMA-PVA thinfilm is estimated to be 4.069 eV. Consequently, bandgap engineering and manipulation of optical properties are possible. Additionally, refractive indices (n) of undoped PMMA-PVA polymeric thin films are calculated to be in the range (1.48-1.72). To elucidate and identify vibrational modes of thin films, Fourier-transform infrared spectroscopy (FTIR) is employed in the spectral range (500 cm − 1-4000 cm − 1). The results obtained are useful for a better understanding of the lattice dynamics. Moreover, thermal stability of thin films is investigated using thermogravimetric (TGA) technique. Remarkably, TGA thermograms reveal that doped thin films are thermally stable below 110C. Consequently, investigated thin films may have the potential to be key candidates for realtime optical and optoelectronic devices.
Journal of Materials Science: Materials in Electronics, 2020
In this work, a detailed insight to the microstructure, morphology, surface topography, electrical and optical properties in visible and terahertz range was presented for polyethylene oxide (PEO)/silicon dioxide SiO 2 nanocomposites. PEO-filled with various contents of SiO 2 nanoparticles were synthesized via the solution cast technique. The polycrystalline nature of PEO/SiO 2 films was affirmed by the selected area electron diffraction pattern (SAED) recorded by HRTEM measurement and it was found to nearly conformable with X-ray diffraction data. The energy-dispersive X-ray analysis (EDAX) proved the existence of SiO 2 with wt% ranged from 0 to 5% as starting fillers. The high-resolution scanning electron microscope planar images indicated uniform distribution of SiO 2 nanoparticles within the PEO films. The atomic force microscope 3D images depicted the surface changed from rough to smooth upon the filling with SiO 2. The composite samples exhibit absorption spectra that extended from UV-Vis to near infrared regions. Based on Tauc's formula, it was found that the absorption edge shifted from 4.90 to 3.20 eV as the filler fraction increased from 0 to 5 wt%. The analysis of reflective index in the UV-Vis-NIR regions displayed decrement with increasing filler content. Moreover, the refractive index in Vis-NIR regions is good extension to that in THz region expressing the optical quality of studied films. The optical dispersion parameters were analyzed in the view of Wemple-Didomenico single oscillator and Sellmeier model. The values of nonlinear optical parameters (nonlinear susceptibility χ (3) and nonlinear refractive index (n 2) were influenced by the filler fractions. Upon the rise of filler content, the conductivity values show slightly decrement.
Study the Effect Doping (Al 2 O 3 ) Nanoparticles on Optical Properties for PVA Polymer
NeuroQuantology, 2022
Polyvinyl alcohol polymer is a harmless substance of great importance to the medical and optical fields. In this paper, we saturated PVA with Al2O3 nanoparticles with different weights 0, 0.01, 0.03 and 0.05% at a temperature of 25 o C and 1 atm pressure, The optical constants had been characterized by measuring the transmittance in the visible spectrum, the ultraviolet field, the absorption, and the rest of the optical properties such as the damping and refraction coefficient, in addition to the real and imaginary part of the dielectric constant and finally the optical conductivity of the samples. We observed that the band gap width (Eg) decrease when we increase the Al2O3 (doping ratio).
2011 14th International Symposium on Electrets, 2011
Polycarbonate nanocomposite containing silicon oxide nanoparticles average size of 5 nm at different weight ratio has been prepared by solution mixing method. The dispersion of nanoparticles in polymer matrix was studied by transmission electron microscopy (TEM). The optical and thermally stimulated behavior of nanocomposites were analyzed by energy dispersive X-ray spectra (EDX), X-ray diffraction pattern (XRD), UV-vis spectroscopy, differential scanning calorimetry (DSC), and thermally stimulated discharge current (TSDC). TEM images show the dispersion and size of the nanoparticles, however, EDX indicate the presence of SiO 2 on the surface of the nanocomposite film. An XRD result reveals that the crystallinity increases with increase in concentration of SiO 2 nanoparticles in polymer matrix. The direct and indirect optical energy band gaps decreased and number of carbon atom increased with concentration of SiO 2 nanoparticles. We have observed that the increase of SiO 2 nanoparticles in PC significantly reduces the refractive index. DSC and TSDC show that glass transition temperature increases according to SiO 2 weight ratio. The TSDC of nanocomposites samples could be understand in terms of non-Debye theory of charge relaxation and co-tunneling mechanism of charge transport. V
Journal of Inorganic and Organometallic Polymers and Materials
The functionalized polyvinyl alcohol (PVA) based nanocomposites thick films of 80 μm containing 1–3 wt% zinc oxide (ZnO) nanoparticles (NPs) were studied. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and Raman spectroscopy were utilized for studying the structural parameters and formed chemical bonds of the synthesized PVA-ZnO films. In addition, extensive characterization has been done on their linear and nonlinear optical properties. The structural analysis of the PVA-ZnO nanocomposites revealed the formation of a wurtzite hexagonal ZnO phase embedded inside the monoclinic PVA phase. The interaction between Zn–O, and functional groups of the PVA as well as the molecular vibration exhibited in the PVA-ZnO nanocomposites were confirmed by the Raman and FTIR spectroscopy and revealed that the PVA-ZnO is a hybrid nanocomposite. The incorporated ZnO NPs ratios slightly affect the PVA films' structure, meanwhile, exhibited a detectable change in the linea...
European Polymer Journal, 2007
Nanocomposites of poly(vinyl alcohol)/silica nanoparticles (PVA-SNs) were prepared by in-situ radical copolymerization of vinyl silica nanoparticles functionalized by vinyltriethoxysilane (VTEOS) and vinyl acetate with benzoyl peroxide (BPO, i.e., initiator), subsequently saponified via direct-hydrolysis with NaOH solution. The resulting vinyl silica nanoparticles, PVA-SNs were characterized by means of fourier transformation spectroscopy (FTIR), transmission electron microscopy (TEM) and elemental analysis method. Effects of silica nanoparticles on viscosity and alcoholysis of PVA-SNs were studied by an ubbelohode capillary viscometer and back titration method. The morphological structure of PVA-SNs film was investigated by scanning electron microscopy (SEM). Differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and tensile test were used to determine the thermal and mechanical properties of PVA-SNs films. The results indicated that the content of vinyl group on the surface of the vinyl silica nanoparticles was up to 3.02 mmol/g and vinyl silica nanoparticles had been successfully copolymerized with vinyl acetate. Furthermore, compared to pure PVA, silica nanoparticles bonded with polymer matrix in low concentration affected the viscosity and alcoholysis of the PVA-SNs materials. At the same time, it resulted in the improvement of the thermal and mechanical properties of the PVA-SNs materials due to strong interaction between silica nanoparticles and polymer matrix via covalent bond. Also, it could be found that optical clarity of membrane was changed through UV-Vis absorption spectrum because of introduction of silica nanoparticles.