Browsing by Author "Osma, Busra"

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Citation Count: 0
The Effect of Pyranine and MoS₂ Content on the Optical Properties of Polyacrylamide-MoS₂ Composite Gels
(Taylor & Francis inc, 2024) Uysal, Bengu Ozugur; Osma, Busra; 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.
Citation Count: 0
Kinetics models for polyacrylamide-graphene oxide composites as antifoulant
(Wiley, 2023) Osma, Busra; Pekcan, Onder; Evinguer, Gulsen Akin
Antifouling paints are used to protect the surface against these organisms such as algae, sea squirts, and barnacles. According to previous research, fish and seaweeds do not adhere to submerged surfaces using wet and soft hydrogels. The aim of this study is to investigate the temperature effect on the performance of antifouling composites to develop new useful antifouling composites for shipping sector. In this swelling experiment, the behavior of hydrogels produced from polyacrylamide (PAAm) and graphene oxide (GO) was investigated at different temperatures. Free-radical cross-linking copolymerization formed composite, using acrylamide, ammonium persulfate, N, N & PRIME;-methylenebisacrylamide (BIS, Merck), and graphene oxide with various contents. The steady-state fluorescence technique was used for studying the swelling of PAAm-GO composites at various temperatures in pure water. When pyranine fluorescence intensity, I was measured, it decreased until swelling equilibrium was achieved. After the swelling experiment was started, the fluorescence emission (I-em) and scattering light intensities, I-sc from different GO content hydrogels were observed by real-time monitoring at various temperatures. Li-Tanaka and Fickian models were used to determine the diffusion coefficients for the swelling experiments in distilled and Marmara Sea Water for 8 and 50 mu l of GO content hydrogels, respectively. According to literature, PAAm is utilized as a surface coating material to reduce biofouling, for this reason, this research will show a way to be able to use PAAm inside antifouling paints material for the marine industry.