Özuğur Uysal, Bengü

Özuğur Uysal, Bengü

Name Variants

Özuğur Uysal, Bengü
B.,Özuğur Uysal
B. Özuğur Uysal
Bengü, Özuğur Uysal
Ozugur Uysal, Bengu
B.,Ozugur Uysal
B. Ozugur Uysal
Bengu, Ozugur Uysal
Uysal, Bengü Özuğur
Özuğur, B
Uysal, Bengü Özuğur
Uysal, Bengu Ozugur
Uysal, Bengü Özuğur

Job Title

Dr. Öğr. Üyesi

Email Address

Bozugur@khas.edu.tr

Main Affiliation

Molecular Biology and Genetics

Status

Former Staff

Full item page

Scholarly Output

28

Articles

21

Citation Count

0

Supervised Theses

5 Scholarly Output Search Results

Now showing 1 - 10 of 11

Citation - WoS: 9
Citation - Scopus: 9
The Ws(2)dependence on the Elasticity and Optical Band Gap Energies of Swollen Paam Composites
(Sage Publications, 2020) Evingür, Gülsen Akın; Özuğur Uysal, Bengü; Sağlam, Nafia Alara; Pekcan, Mehmet Önder; Çimen, Büşra; Uysal, Bengü Özuğur; Pekcan, Önder
New generation nano-filler polymer composites have many applications including biomedical, electronic and maritime related applications because of their mechanical, electronic and optical properties. The properties of composites were investigated as a function of nano-filler content. Among these, tungsten disulfide (WS2) has the potential to be used as a component in electronic devices owing to its high electron mobility and easily tunable optical band gap energy. Tungsten disulfide (WS2)- Polyacrylamide (PAAm) composite was prepared using free radical co-polymerization and wet laboratory methods with WS(2)content. Composites were characterized for mechanical and optical properties using an Elasticity Instrument and UV-vis Spectrophotometer, respectively. Elastic modulus was modeled by a statistical thermodynamics model. Tauc's and Urbach's Tail model for direct transition were used to model for the optical band gap. In this study, the swelling and WS(2)effect on the optical band gap and elasticity of WS2- PAAm composites were investigated. It was observed that the elasticity presented a reversed behavior of optical band gap energies with respect to WS(2)content. For the applications of nano-filler doped polymer composites in flexible electronic devices, WS(2)content strongly influences the mechanical and optical properties.
Citation - WoS: 2
Citation - Scopus: 2
Fractal Features and Structural Morphological Optical Characteristics of Sol-Gel Derived Silica Nanoparticled Thin Films
(Polish Acad Sciences Inst Physics, 2018) Uysal, Bengü Özuğur; Özuğur Uysal, Bengü; Pekcan, Önder; Pekcan, Mehmet Önder
Nanostructured silica films using a simple and effective sol-gel spin coating technique were synthesized and the influence of ammonia/sol ratios on the particle size and thickness of this film was investigated. In addition fractal dimensions of the prepared films were determined using the scattering response technique. The samples were characterized by atomic force microscopy and UV-vis spectroscopy. Comparing optical method and image analysis of atomic force microscopy micrographs the fractal dimension of silica nanoparticled thin films was determined. The fractal dimensions of the films verified by atomic force microscopy analysis were found to be around 2.03 which is very close to the values (2.0358 2.0325 and 2.0335) obtained using optical method. As a result of these findings precise determination of the nanoparticled silica thin films fractal dimension using both optical and surface analysis methods was realized.
Citation - WoS: 2
Citation - Scopus: 1
3D self-assemble formation of molybdenum disulfide (MoS2)-doped polyacrylamide (PAAm) composite hydrogels
(Tubitak Scientific & Technological Research Council Turkey, 2022) Özuğur Uysal, Bengü; Pekcan, Mehmet Önder; Uysal, Bengu Ozugur; Pekcan, Onder
Polyacrylamide (PAAm), a renowned member of the hydrogel class, has many uses throughout a wide range of industrial processes, including water absorbed diapers, contact lenses, wastewater treatment, biomedical applications such as drug delivery vehicles and tissue engineering because of its physical stability, durability, flexibility easier shaping, and so on. PAAm also provides new functionalities after the incorporation of inorganic structures such as molybdenum disulfide (MoS2). During the copolymerization process, the transmittance of all samples reduced significantly after a particular time, referred to as the gel point. Microgels form a tree above the gel point as projected by Flory-Stockmayer classical theory. Because of microgels positioned at the junction points of the Cayley tree, the addition of MoS2 results in strong intramolecular crosslinking and looser composites. Moreover, fractal geometry provides a quantitative measure of randomness and thus permits characterization of random systems such as polymers. Fractal dimension of these polymer composites is calculated from power-law-dependent scattered intensity. It was also confirmed that a hydrogel rapidly formed within a few seconds, indicating a 3D network formation inside the gel. These materials may have a great potential for application in wearable and implantable electronics due to this highly desired 3D self-assemble feature.
3d Self-Assemble Formation of Molybdenum Disulfide $(mos_2 )-Doped$ Polyacrylamide (paam) Composite Hydrogels
(2022) Durmaz, Sümeyye; Özuğur Uysal, Bengü; Yıldız, Ekrem; Pekcan, Mehmet Önder; Uysal, Bengü Özuğur; Pekcan, Önder
Polyacrylamide (PAAm), a renowned member of the hydrogel class, has many uses throughout a wide range of industrial processes, including water absorbed diapers, contact lenses, wastewater treatment, biomedical applications such as drug delivery vehicles and tissue engineering because of its physical stability, durability, flexibility easier shaping, and so on. PAAm also provides new functionalities after the incorporation of inorganic structures such as molybdenum disulfide $(MoS_2 )$. During the copolymerization process, the transmittance of all samples reduced significantly after a particular time, referred to as the gel point. Microgels form a tree above the gel point as projected by Flory-Stockmayer classical theory. Because of microgels positioned at the junction points of the Cayley tree, the addition of $MoS_2$ results in strong intramolecular crosslinking and looser composites. Moreover, fractal geometry provides a quantitative measure of randomness and thus permits characterization of random systems such as polymers. Fractal dimension of these polymer composites is calculated from power-law-dependent scattered intensity. It was also confirmed that a hydrogel rapidly formed within a few seconds, indicating a 3D network formation inside the gel. These materials may have a great potential for application in wearable and implantable electronics due to this highly desired 3D self-assemble feature.
Citation - WoS: 2
Citation - Scopus: 3
Tailoring the Electrical and Optical Properties of Carbon Nanotube Reinforced Transparent Tio 2 Composites by Varying Nanotube Concentrations
(World Scientific Publ Co Pte Ltd, 2019) Uysal, Bengü Özuğur; Özuğur Uysal, Bengü; Akkaya Arier, Ümit Özlem; Pekcan, Mehmet Önder; Pekcan, Önder
In the present work multi-walled carbon nanotube (MWCNT)-doped TiO 2 nanocomposite films were synthesized by sol-gel method. The influence of nanotube concentration on the structural electrical and optical properties of the films was investigated. The beneficial effects of the addition of carbon nanotubes into a TiO 2 film and titania-coated MWCNTs have much in common. On the other hand this work contributes to the previous studies in terms of the optical and electrical properties of MWCNT. For this reason MWCNT/rare brookite-phased TiO 2 matrix as simple sol-gel deposited composite films were investigated in our study. The XRD studies showed that the composite film has a brookite crystal structure at the annealing temperature of 450C. According to the surface morphology investigations SEM image of nanocomposite film shows that composite film has a granular and rod-like structure. The absorbance measurements of the films were carried out by the UV-Vis spectrophotometer to investigate transparency and to calculate the bandgap energy of composite films. The surface resistivity of the MWCNT-doped TiO 2 composites decreased from 2.50×1010 to 2.20×109 ohm/sq with increase in MWCNT content. © 2019 World Scientific Publishing Company.
Citation - WoS: 3
Citation - Scopus: 4
Tungsten Disulfide (ws2) Doped Polyacrylamide (paam) Composites: Gelation and Optical Studies
(Elsevier Gmbh, 2021) Nayir, Sseyma; Özuğur Uysal, Bengü; Kivrak, Sena; Pekcan, Mehmet Önder; Kara, Iirem; Uysal, Bengu Ozugur; Pekcan, Oonder
The organic Acrylamide (AAm) copolymerization in various contents of inorganic WS2 has been reported. The aim was to investigate the effect of the WS2 amount on the obtained morphology and the gelation process of the AAm composites. It was found that during gelation process the photon intensity of transmission decreased significantly above some critical time, called the gel point, tg. The decrease in the photon intensity of transmission was related to the increase in the intensity of scattered light from the gel attributable to the production of microgel that occurs while copolymerization held in AAm with Bis-Acrylamide (BIS). Gel points were found to be increased by increasing WS2 content. Time-dependent scattering of composites manifests the growth mechanism, the greater microgel particles, as in agreement with Rayleigh's equation of scattering. It is determined that concentration of microgels is inversely proportional to the WS2 content. The composite rate constants of gelation, kr were produced and observed that it is proportional to WS2 content. It is understood that inclusion of WS2 in AAm system during gelation delays the process at early times but then contributes to increase the gelation process by increasing the rate of polymerization. Besides less compact PAAm gels are produced in the presence of WS2 atoms. It is also shown that the microgel growth mechanism and gel point of PAAm composite incorporated with WS2 can be significantly tailored by the amount of WS2. Tunable growth mechanism and critical gelation point is crucial for flexible electronic applications.
Citation - WoS: 10
Citation - Scopus: 8
Surfactant-Free One-Step Fabrication of Gelatin/Paam Composites for Biomedical Applications
(Springer, 2021) Duzkan, Berke; Özuğur Uysal, Bengü; Uysal, Bengü Özuğur; Pekcan, Mehmet Önder; Pekcan, Önder
Well-dispersed multiwalled carbon nanotube (MWCNT) and gelatin-enhanced polyacrylamide (PAAm) composites were synthesized via a free-radical copolymerization method. MWCNTs were added to the composite mixture in various amounts (0.5 mg, 1.0 mg, 1.5 mg, and 2.0 mg) during the nucleation process in order to increase the conductivity. Gelatin/PAAm/MWCNT composites containing different amounts of MWCNTs were then characterized using the ultraviolet-visible (UV-vis) spectroscopic technique to illuminate the dispersibility, and optical properties of the composites. Bandgap energies were evaluated by measuring the absorbance spectra of the composites in a quartz cuvette of the UV-vis spectrophotometer. By calculating the resonance ratio and normalized width values from the absorption response of the composites according to the wavelength, the dispersion rate of the MWCNTs in the composite matrix was determined. The proper ultra-sonication process has been realized so as to maintain the good dispersion of the MWCNTs inside the polymeric matrix lowering the normalized width and increasing the resonance ratio. Polymeric composite materials based on carbon nanotubes are of considerable interest for a variety of biomedical applications. Furthermore, in this work, it is argued that the use of gelatin, another biocompatible material, together with MWCNT makes the properties of the formed composite, suitable for the desired biomedical applications.
Citation - WoS: 4
Citation - Scopus: 5
Polyacrylamide Mediated Polyvinyl Pyrrolidone Composites Incorporated With Aligned Molybdenum Disulfide
(Wiley, 2022) Uysal, Bengu Ozugur; Özuğur Uysal, Bengü; Evingur, Gulsen Akin; Pekcan, Mehmet Önder; Pekcan, Onder
In this study, we aimed to design a mechanically durable material consisting of Molybdenum disulfide (MoS2) as 2D material and polyvinyl pyrrolidone (PVP) enhanced Polyacrylamide (PAAm) composites. Composites containing different amounts of MoS2 were synthesized via a free-radical crosslinking copolymerization method. They were characterized using UV-visible spectroscopy, fluorescence, and mechanical techniques to illuminate band gap energy, absorption, slow release kinetics, and modulus of the composites. Furthermore, the effect of swelling on the elasticity of the composites was investigated. It was observed that the elasticity exhibited similar band gap energies with respect to the MoS2 content. The results demonstrated that the MoS2 content strongly influences the optical and mechanical properties of the composites and consequently physical parameters of the composites have been correlated with the various amounts of MoS2.
Citation - WoS: 108
Citation - Scopus: 114
Efficient Photocatalytic Degradation of Methylene Blue Dye From Aqueous Solution With Cerium Oxide Nanoparticles and Graphene Oxide-Doped Polyacrylamide
(Amer Chemical Soc, 2023) Kalaycioglu, Zeynep; Özuğur Uysal, Bengü; Uysal, Bengu Ozugur; Pekcan, Mehmet Önder; Pekcan, Onder; Erim, F. Bedia
A cerium oxide nanoparticles (CeO2-NPs)/graphene oxide (GO)/polyacrylamide (PAM) ternary composite was synthesized through free-radical polymerization of acrylamide in the presence of CeO2 nanoparticles and GO in an aqueous system. The synthesized composite material was characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and energy-dispersive X-ray (EDX) spectroscopy techniques and applied for the photocatalytic degradation of methylene blue (MB) dye from an aqueous solution. Tauc's model for direct transition was used to model for the optical band gap. The key operating parameters such as the amounts of CeO2-NPs and GO, pH, initial MB concentration, type of light irradiation, and contact time have been optimized to achieve the highest MB degradation percentage. The photocatalysis process was pH-dependent, and the optimum pH value was found to be 12.0. Under UV-A light, 90% dye degradation occurred in 90 min. The degradation of MB was also specified in terms of total organic carbon (TOC) and chemical oxygen demand (COD). Free-radical capture experiments were also performed to determine the role of radical species during the photocatalytic oxidation process. The photocatalytic process showed that the equilibrium data is in good agreement with the Langmuir-Hinshelwood kinetic model. A rate constant of 0.0259 min-1 was obtained. The hydrogel was also tested to assess its reusability, which is an important key factor in practical wastewater treatment. The photocatalytic activity only decreased to 75% after nine uses.
Citation - WoS: 0
Citation - Scopus: 0
The Effect of Pyranine and Mos₂ Content on the Optical Properties of Polyacrylamide-mos₂ Composite Gels
(Taylor & Francis inc, 2024) Uysal, Bengu Ozugur; Özuğur Uysal, Bengü; Osma, Busra; Pekcan, Mehmet Önder; Evingur, Gulsen Akin; Pekcan, Onder
The most favorable members of the class of two-dimensional (2D) materials, molybdenum sulfide (MoS2), graphene, and tungsten disulfide (WS2) have become a thriving research frontier for many applications, ranging from catalysis to optoelectronic devices, due to their superior electronic behavior and mechanical properties. Making a new, smart, hydrogel when incorporating MoS2 into basic hydrogels can change their optical, electronic, and mechanical properties. In this work, MoS2-doped polyacrylamide (PAAm) gels were prepared via the free radical crosslinking copolymerization technique at room temperature without pyranine which is often used for crosslinking PAAm. The optical properties of PAAm-MoS2 composite gels were investigated, and they were analyzed using ultraviolet (UV) and fluorescence spectroscopy. The absorbance was measured before and after diffusion of MoS2-doped PAAm, and after the release of pyranine in and out of the composite gel, respectively. The shift of the absorption edge toward shorter wavelengths was seen when the quantity of MoS2 in the PAAm composite gels was decreased. The constituents included in the polymer composites exhibited notable photon energy absorption within the visible and ultraviolet spectra. This absorption phenomenon induced electron transitions to states of elevated energy. Parameters, such as refractive index and extinction coefficient, were analyzed with respect to the content of MoS2. When the MoS2 amount was increased in the gels, the percentage of reflectance increased. The extinction coefficient increased at longer wavelength and it decreased in the UV range, the shorter wavelength region. The results suggested that MoS2-doped PAAm composite gels show promising optoelectronic properties for developing optoelectronic devices.