Ahmed Yassin Yassin
@deltauniv.edu.eg
Department of basic sciences
Delta University for Science and Technology
RESEARCH INTERESTS
Nanocomposites; Solid state physics; Polymer physics
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
I. S. Elashmawi, A. M. Ismail, A. M. Abdelghany, M. M. Hegazi, and A. Y. Yassin
Springer Science and Business Media LLC
AbstractThin polymeric films of poly(vinylidene fluoride) (PVDF) containing variable mass fractions of nanoparticles (LiZnVO4) were successfully synthesized via the ordinary solution casting method. X-ray diffraction (XRD), Fourier transform infrared (FT-IR), and ultraviolet–visible spectroscopy were used to explore the role of LiZnVO4 on the structural and optical characteristics of synthesized nanocomposites. In addition, dielectric permittivity (ε' and ε") and dielectric modulus (M' and M") were investigated. The XRD spectral data reveals the crystalline nature of pure LiZnVO4 with rhombohedral structure with an average size of 83 nm calculated using the Scherrer’s equation and W-L plot. The interaction between PVDF and LiZnVO4 was approved through the shift in characteristics in some IR bands. The decrease in band gap energies with increasing LiZnVO4 was attributed to the change of density in the localized states within the PVDF matrix. The effect of both frequency and temperature on the AC parameters was also investigated. Both ε' and ε" had their maximum values at low frequencies and decreased as the frequency and temperature increased. The results from XRD and FT-IR were correlated with changes in the dielectric characteristics at the maximum level value of LiZnVO4, suggesting the potential of these materials as basic components for lithium-ion batteries.
Mohammed M. Damoom, Abdu Saeed, Eida M. Alshammari, Abdulsalam M. Alhawsawi, A. Y. Yassin, J. A. Mohammed Abdulwahed, and A. A. Al-Muntaser
Springer Science and Business Media LLC
Amira M. Salem, A. Raouf Mohamed, and A. Y. Yassin
Springer Science and Business Media LLC
AbstractThe current work aims to synthesize carboxymethyl cellulose/polypyrrole (CMC/PPy) blends with different PPy concentrations as promising blends for energy storage devices with low cost and excellent chemical and physical characteristics. The structural and dielectric characteristics of CMC/PPy blends were studied. FT-IR spectroscopy is utilized to study the structural properties of the present blends, whereas the dielectric properties are explored at frequency range of 0.1 Hz−20 MHz. The structural study of CMC/PPy blends showed good homogeneity between the CMC matrix and PPy as a conductive filler. The thermal behavior of the present blends was also investigated using DSC, where the thermal stability of the blends was improved after incorporating PPy into the host matrix. The dielectric characteristics results indicated a rise in the dielectric parameters of CMC with an increase in the PPy content up to 8 wt%. The dielectric parameters of CMC/PPy blends are frequency dependents. The dielectric constant (ε′) and AC electrical conductivity of the blends under study enhanced by about 33% with a rise in the PPy content to 8 wt%. The dielectric loss (ε″) values decreased from 3.4938 to 0.93071 at 10 kHz; this performance means that the CMC/PPy blends have an excellent possibility for energy storage devices with low dielectric loss in various applications, such as sensors, batteries, and capacitors.
E. M. Abdallah, G. M. Asnag, M. A. Morsi, Marwah Aljohani, Aisha Nawaf Albalwa, and A. Y. Yassin
Wiley
A. Y. Yassin, A. M. Abdelghany, Reda S. Salama, and A. E. Tarabiah
Springer Science and Business Media LLC
AbstractIn this work, zinc oxide (ZnO) was produced using extracts of Thymus (Z), Hibiscus rosa-sinensis (K), and Daucus carota (G). Furthermore, sodium carboxymethyl cellulose (CMC) and polyvinyl alcohol (PVA) were combined with ZnO to form three novel nanocomposites. X-ray diffraction (XRD) was used for the structural analysis, where the semicrystalline nature of the (CMC/PVA)/ZnO nanocomposites was confirmed. The characteristics functional groups that arose inside the prepared samples were identified by Fourier transform infrared spectroscopy (FTIR). Evidence for the successful preparation of the pure ZnO particles and their nanocomposites was carried out using a transmission electron microscope (TEM). The ZnO nanoparticles are mostly spherical, irregularly distributed, and have radii ranging from 10 to 40 nm. Their anti-bacterial activity was studied against B. subtilis, E. coli, and Candida albicans. The inhibition zones of all the prepared samples against E. coli were 0, 19, 31, and 23 mm for PVA/CMC blend, PVA/CMC/ZnO (Z) (PCZ-Z), PVA/CMC/ZnO (K) (PCZ-K), and PVA/CMC/ZnO (G) (PCZ-G), respectively, compared to the streptomycin control Gram-positive standard with inhibition zone (34 mm). On the other hand, the inhibition zones of the prepared samples against B. subtilis were equal to 0, 26, 33, and 28 mm for CMC/PVA, PCZ-Z, PCZ-K, and PCZ-G, respectively. Based on these results, the PCZ-K sample is the most effective at resisting E. coli (91.17%) and B. subtilis (94.28%). These nanocomposites do not have harmful chemicals, making them strong candidates for use in biological applications.
A. A. Al-Muntaser, Rami Adel Pashameah, Abdu Saeed, Reem Alwafi, Eman Alzahrani, Samah A. AlSubhi, and A. Y. Yassin
Springer Science and Business Media LLC
A. Y. Yassin
Springer Science and Business Media LLC
AbstractIn the present work, gold nanoparticles (Au-NPs) were synthesized in two ways: plant extract and laser ablation techniques. Then, Au-NPs were added to (PVP/PVA/CMC) blend (TB) to produce novel nanocomposites using the solution casting technique. X-ray diffraction analysis, Ultraviolet and visible spectroscopy, and transmission electron microscopy provided conclusive evidence for preparing Au-NPs through the above methods. The optical, structural, and dielectric properties of the prepared samples were prudently investigated and confirmed their semicrystalline nature. TEM study concluded that Au-NPs are more uniformly distributed in the TB/AuNPs-biosynthesized (TBAu-B) matrix than in the TB/Au-NPs prepared by laser ablation (TBAu-L) matrix. The decrease in interatomic distances increases the refractive index with an enhancement in optical properties. The change in loss tangent provided a deeper discernment into the relaxation dynamics that arose inside the current films. The electric modulus formalism verified the non-Debye behavior of charge carriers inside the TB-based nanocomposite samples. It also demonstrated a remarkable capacitive feature of the nanocomposite films. The dielectric characteristics of the TBAu-B nanocomposite sample have improved, where AC electrical conductivity reached 1.58 × 10−3 S/cm. Because of this favorable enhancement, the TBAu-B nanocomposite has the potential to be utilized in optoelectronic applications such as sensors.
Amira M. Salem, A. Raouf Mohamed, A.M. Abdelghany, and A.Y. Yassin
Elsevier BV
A.Y. Yassin, A.M. Abdelghany, M.M. Shaban, and Y.M. Abdallah
Elsevier BV
A.Y. Yassin and A.M. Abdelghany
Elsevier BV
A. Y. Yassin
Springer Science and Business Media LLC
A (PVA–PVP)-based polymer electrolyte doped with different concentrations of nickel chloride hexahydrate (NiCl2·6H2O) and cadmium chloride hexahydrate (CdCl2·6H2O) as a mixed filler with ratio (50:50) was synthesized by solution casting technique. Thermal behavior, mechanical and dielectric properties of the prepared composite samples were carefully studied. Relaxation process of the induced charge carriers was also discussed, where three relaxation processes, namely αβ-, β- and βγ-relaxations were found and were associated with the amorphous nature of (PVA–PVP)/(Ni–Cd) composite. The growth in amorphous regions facilitates the rotational motion of (O–H, N–O and C=O) dipolar groups and movement of single polarons, enhancing the interfacial and dipolar polarization and consequently the dielectric properties. The considerable decrease in activation energy (Erelax), relaxation time (τ), dielectric modulus (M′′) and loss tangent (tan δ) values in addition to free volumes arose inside the polymeric matrix confirmed the strong interaction between composite constituents. The dielectric nature of (PVA–PVP) blend and the conductive nature of (Ni–Cd) fillers helped in composing microcapacitors inside the present polymeric matrix. Additionally, the tensile strength has increased from 5.55 MPa to 21.4 MPa, whereas Young’s modulus has improved from 340.52 to 1706.82 MPa. This constructive enhancement in dielectric and mechanical properties suggests exploiting the (PVA–PVP)/(Ni–Cd) composite in manufacturing (Ni–Cd) batteries and energy storage devices.
Ahmed Y. Yassin, Abdel-Raouf Mohamed, Elmetwaly M. Abdelrazek, Muhamed A. Morsi, and Amr M. Abdelghany
Elsevier BV
Abstract Different concentrations of graphene oxide (GO) were successfully embedded into poly (vinyl chloride-co-vinyl acetate-co-2-hydroxypropyl acrylate) (PVVH) copolymer. The composites obtained were characterized using XRD, FT-IR, SEM and UV/Vis techniques, in addition to investigating their electrical properties. XRD results showed the predominance of the amorphous phase inside the prepared samples. The main characteristic peaks of the used materials were observed in FT-IR spectra with changes in their intensities and/or their positions, confirming the successful complexation and strong interaction between GO and PVVH. A bathochromic shift in the main absorption sharp edge was detected in UV/Vis spectra. Additionally, the two peaks at 214 and 280 nm were ascribed to n→π* and π→π* transitions, respectively. Both optical energy gap and refractive index were calculated in terms of UV/Vis absorption spectra using Mott–Davis model and Dimitrov–Sakka equation. The thermal behavior of the current samples was carefully investigated by employing TGA. Moreover, the activation energy was studied using Coats-Redfern and Broido models. The homogeneous dispersion of GO has contributed to the significant increase in the electrical conductivity as well as improving thermal stability of the PVVH-based nanocomposites. The experimental results obtained for the current system promote these nanocomposites for use in optoelectronic applications.
A. Y. Yassin, A. Raouf Mohamed, A. M. Abdelghany, and E. M. Abdelrazek
Springer Science and Business Media LLC
Synthesis of a new nanocomposite composed of poly (vinyl chloride-co-vinyl acetate-co-2-hydroxypropyl acrylate) (PVVH) copolymer and graphene oxide (GO) was successfully achieved using solution casting technique. Dielectric properties of the nanocomposite were investigated in the frequency range (10 Hz to 10 MHz) over the temperature range (298–373 K). Many variables such as: dielectric constant, dielectric loss, loss tangent, electric moduli and AC conductivity were studied with changing frequency and temperature, showing improvement in the nanocomposite properties with both of them. The non-Debye behaviour of the samples was confirmed from the electric modulus analysis. AC conductivity (σac) was found to follow Jonscher’s universal power law. The enhancement in (σac) with frequency and temperature has implied the presence of free charge carriers that pass by hopping through defect sites over the potential barriers separating them in the PVVH/GO matrix. The correlated barrier hopping (CBH) model was found to be the best choice for describing AC conduction mechanism in the current nanocomposite over the above temperature range. Scaling of (σac) carried out for the prepared samples has exhibited that charge carriers within the current matrix follow a common conduction mechanism. A comparison between maximum barrier height and activation energy has been carried out to demonstrate the charge carriers transport mechanism. The PVVH-based nanocomposite with the highest concentration of GO (4 wt%) has achieved the highest enhancement in (σac) and mechanical properties, suggesting the feasibility of using it in designing electrochemical and energy storage devices.
E.M. Abdelrazek, I.S. Elashmawi, A. El-khodary, and A. Yassin
Elsevier BV
Films of PVA/PVP blend (50/50) filled with different concentrations of LiBr were prepared. The prepared films were investigated by different techniques. XRD scans demonstrate that complexation between the filler and the blend takes place in the amorphous region. UV–VIS analysis revealed that the values of the optical energies are changed with increase Li-ions content. This indicates that there is a charge transfer complexes arise between the polymer blend and Li-ions. The thermal stability of the product samples has improved after filling LiBr increases, this indicates that the filler acts as a plasticizer. The rise of the conductivity is significant with increased concentration of LiBr, this is means the decrease in the degree of crystallinity and increase in the degree of amorphosity. This suggests the choice of LiBr as filler to improve the electrical conductivity of PVA/PVP.