Çanakçı, Dilek; Sarıbıyık, Oğuz Yunus

In this work, novel triazine-containing polyamide derivatives possessing thermal stability and magnetic properties were synthesized. The synthesis process involves two steps: first, the chlorination of adipic acid and succinic acid using thionyl chloride; and second, the amidation of triazine. As a result of these procedures, two different triazine-containing polyamides were synthesized. The synthesized polyamides formed complexes with Ag, Cu, and Zn ions to enhance their thermal stability and magnetic properties.The structures of the synthesized polyamides were elucidated primarily by FTIR analysis, focusing on distinctive bands corresponding to the carbonyl group. The molecular structures of the polyamides were confirmed using 1H NMR and 13C NMR spectroscopy. Scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDX) was employed to obtain information on the morphology and elemental composition of the samples. In addition, X-ray diffraction (XRD) analysis was performed to characterize the crystal structures, unit cell parameters, and orientations of the solid-state metal complexes. The thermal stability of both the polyamides and their metal complexes was investigated using thermogravimetric analysis (TGA). The magnetization of the synthesized compounds was measured as a function of temperature under zero-field-cooled (ZFC) and field-cooled (FC) conditions using a physical property measurement system (PPMS).

Erbakan, Mustafa; Taşdemir, Muharrem; Şenaslan, Fatih; Sarıbıyık, Oğuz Yunus

In this study, we investigated the influence of crystal structure, topography, and elemental composition of aluminum oxide surfaces on bacterial adhesion. The structural properties of the surfaces were systematically controlled by varying the current density (1.5, 2.0, and 2.5 A/dm2) and silver doping during the anodization process. The resulting changes in structural and morphological properties were examined by using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FE-SEM), contact angle measurements, and profilometry. Using FE-SEM analysis, we evaluated the adhesion of model bacteria, Escherichia coli and Staphylococcus aureus, to surfaces exhibiting diverse morphologies and elemental compositions. The surface roughness and crystal size of the aluminum oxide increased proportionally with the applied current density and silver doping. According to the XRD results, the slip plane crystal structure of (311) increased proportionally to the current density but decreased with silver doping. Specifically, while stepped atomic alignment of (311) planes facilitates bacterial attachment, smoother (200) planes reduce the adhered bacteria population. Further analysis via XPS revealed that the oxide crystal structure of undoped surfaces shifted from the tetrahedral to octahedral form with increasing current density, while silver-doped surfaces exhibited the opposite trend. Additionally, increasing current density during the preparation of silver-doped surfaces diminished the ratio of ionic silver to metallic silver, suggesting a lowered propensity for bacterial adhesion. S. aureus adhesion to undoped surfaces increased 4.46-fold for surfaces prepared at 2.5 A/dm2 compared to that at 1.5 A/dm2. Moreover, E. coli adhesion was completely inhibited on silver-doped surfaces anodized at 1.5 A/dm2. Reducing the surface roughness and incorporating silver during the anodization of aluminum surfaces decrease the number of bacteria adhering to aluminum oxide surfaces.

Kaya, Şevval; Sarıbıyık, Oğuz Yunus

Coating of the metal surface for different fields such as corrosion resistance, hydrophobic surface, and conductivity properties enhance the material quality for different application. Furthermore, controlling the morphological structures and the size of the coating materials is one of the most important factors for designing their functionality. The new approaches to the effect of surface properties at the atomic level on bacterial adhesion offer new perspectives on this subject. In this study, the effect of the different current densities on the morphological microstructural features, microhardness properties, and bacterial attachment behavior of the protective aluminum oxide layer was investigated by using different analytical and instrumental methods. The Staphylococcus aureus was used as a model bacteria for attachment tests. The result presented in the current study exhibited that the crystal morphology, microhardness, and bacterial adhesion features have changed depending on the applied current density. Increasing the current density from 1.5 to 1.7 raises the microhardness from 88 to 126 (Vickers) and causes higher surface roughness by 56 nm, 114 nm and 124 nm respectively. The high number of the attached bacteria were determined on the more roughness surface during the study.

Sarıbıyık, Oğuz Yunus; Gönül, İlyas; Ay, Burak; Karaca, Serkan

In this work, an insoluble three dimensional (3D) porous polymeric structure and their metal complexes were synthesised by the condensation reactions of meta(m)-phenylenediamine, para(p)-phenylenediamine and glutaraldehyde. The morphological and spectral features of the porous polymeric structures were determined using different analytical and spectroscopic methods, including field emission scanning electron microscopy, four-point probe electrical conductivity, photoluminescence spectroscopy, Fourier-transform infrared spectroscopy, surface area Brunauer–Emmett–Teller and magnetic and thermal behaviours. According to the obtained data, the shape, size and photoluminescence properties of the compounds, especially the conductivity, were clearly changed after the metalation processes.

Sarıbıyık, Oğuz Yunus; Rupprechter, Günther; Weilach, Christian; Serin, Selahattin

Tailoring the shape of nanoscale materials enables obtaining morphology-controlled surfaces exhibiting specific interactions with reactants during catalytic reactions. The specifics of nanoparticle surfaces control the catalytic performance, i.e., activity and selectivity. In this study, shape-controlled Platinum (Pt) and Palladium (Pd) nanoparticles with distinct morphology were produced, i.e., cubes and cuboctahedra for Pt and spheres and polyhedra/multiple-twins for Pd, with (100), (111 + 100), curved/stepped and (111) facets, respectively. These particles with well-tuned surfaces were subsequently deposited on a Zirconium oxide (ZrO2 ) support. The morphological characteristics of the particles were determined by high resolution transmission electron microscopy (HR-TEM) and X-ray diffraction (XRD), while their adsorption properties were investigated by Fourier transform infrared spectroscopy (FTIR) of CO adsorbed at room temperature. The effect of the nanoparticle shape and surface structure on the catalytic performance in hydrodechlorination (HDCl) of trichloroethylene (TCE) was examined. The results show that nanoparticles with different surface orientations can be employed to affect selectivity, with polyhedral and multiply-twinned Pd exhibiting the best ethylene selectivity.