Scopus İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/395
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Article Citation - WoS: 7Citation - Scopus: 7Unveiling the Multifaceted Properties of a 3D Covalent-Organic Framework: Pressure-Induced Phase Transition, Negative Linear Compressibility and Auxeticity(Elsevier, 2023-08) Erkartal, MustafaHigh-pressure behavior and mechanical properties of a three-dimensional covalent-organic framework (NPN-1) were investigated by using different types of first principles molecular simulations. An irreversible pressureinduced first-order isosymmetric phase transition was predicted at 0.14 GPa. The subunit of NPN-1 retains its rigidity under pressure thanks to the strong covalent bonds. However, compression leads to significant tilting of the nitrophenyl groups. The mechanical properties of frameworks are highly anisotropic. Remarkably, both phases exhibit not only negative linear compressibility along the c-axis but also negative Poisson's ratio in certain directions. Detailed structural analysis revealed that the origin of the phase transition and anomalous mechanical properties of both phases are the wine-rack motif and strut-hinge mechanism. To the best of our knowledge, this study is the first report of such behavior in COFs, opening up new avenues for the exploration of COFs as materials for many promising applications.Article Citation - WoS: 8Citation - Scopus: 9Synthesis of Benzotriazole Functionalized ZIF-8 by Postsynthetic Modification for Enhanced CH4 and CO2 Uptakes(Elsevier, 2022-08) Erkartal, Mustafa; Incekara, Kaan; Sen, UnalIn this work, a series of functionalized ZIF-8 were synthesized via incorporation of benzotriazole ligands into the framework with a post-synthetic method. The crystal structure and porosity were preserved for all functionalized samples. Although a relatively low percentage of ligand exchange (approximately 10-22%) was observed due to steric and kinetic effects, a remarkable improvement was found in CO2 and CH4 uptake capacities due to the incorporation of more polar N sites into the structure and the change in pore size of the frameworks. The resulting ZIF-8-S5 exhibited 45.17(CO2) and 15.08 (CH4) cm(3) g(-1) at 273 K under 1.2 bar, which corresponds to an enhancement of 20 and 35% compared to pristine ZIF-8. Further, all functionalized samples showed the significant improvement of selective CO2 over N-2.Article Citation - WoS: 7Citation - Scopus: 7Giant Negative Linear Compressibility, Isosymmetric Phase Transition, and Breathing Effect in a 3D Covalent Organic Framework(Amer Chemical Soc, 2023-12-26) Erkartal, MustafaA set of remarkable piezo-mechanical properties, including isosymmetric phase transition, negative linear compressibility (NLC), and a breathing effect in a three-dimensional covalent organic framework (NPN-3), was uncovered using density functional theory. The pressure-induced first-order phase transition observed between 0.9 and 1 GPa is isosymmetric and irreversible. NPN-3 shows giant NLC along the c-axis (K-c = 42.04 TPa-1) prior to the phase transition. The high-density NPN-3-hd obtained as a result of the phase transition shows an exciting phase transition from a closed pore to an open pore under hydrostatic tensile pressure, similar to the breathing effect. These extraordinary piezo-mechanical attributes within NPN-3 can be attributed to the diamondoid (dia) topology, which is commonly found within flexible MOFs and COFs. Additionally, the remarkable adaptability of the tetraphenyl adamantane monomer to distinct conformations under pressure can be seen in these properties. These findings underscore the potential utility of COFs as materials for piezo-mechanical sensors and serve as a source of inspiration for further exploration into the intricate mechanical behaviors of COFs.Article Citation - WoS: 75Citation - Scopus: 80From 2-Methylimidazole to 1,2,3-Triazole: A Topological Transformation of ZIF-8 and ZIF-67 by Post-Synthetic Modification(Royal Soc Chemistry, 2017) Erkartal, Mustafa; Erkilic, Ufuk; Tam, Benjamin; Usta, Hakan; Yazaydin, Ozgur; Hupp, Joseph T.; Sen, UnalBridging ligand replacement in zeolitic imidazolate frameworks, ZIF-8 and ZIF-67, by 1,2,3-triazole was investigated. A complete substitution of 2-methylimidazole by 1,2,3-triazole resulted in a topological transformation of the parent framework from a sodalite (SOD) network to a diamond (DIA) network.Article Citation - WoS: 6Citation - Scopus: 7Extreme Flexibility and Unusual Piezomechanical Properties of Zinc-Alkyl Metal-Organic Frameworks: A First Principles Study(Elsevier, 2023-06) Erkartal, MustafaThe behavior of three Zn-alkyl-based MOFs, ZnGA (Zn-Glutarate), ZnAA (Zn-Adipate), and ZAG-4 (Zinc Alky Gate), under hydrostatic compression has been investigated using first-principles DFT simulation, which has proven its reliability in previous studies. Due to the lack of the high pressure experimental data for ZnGA and ZnAA, the reliability of the simulation parameters was tested by taking ZAG-4, whose structural flexibility has been previously reported experimentally and computationally, as a benchmark. All three structures were found to exhibit elastic deformation under pressure up to 15 GPa, due to the flexibility of the alkyl chains that allow the structures to move without disrupting the metal-ligand coordination. Interestingly, the structures exhibit different mechanical properties, with ZAG-4 showing negative linear compressibility (NLC), ZnGA showing positive linear compressibility (PLC), and ZnAA showing zero linear compressibility (ZLC). The NLC in ZAG-4 is attributed to the proton transfer between phosphonate oxygen and water in the structure as previously reported, while the ZLC in ZnAA is due to a dumbbell-like structural motif formed by substructures displaying both NLC and PLC.Article Citation - WoS: 17Citation - Scopus: 20Basalt Fiber Reinforced Polymers: A Recent Approach to Electromagnetic Interference (EMI) Shielding(Wiley, 2024-10-09) Fareez, Umar Naseef Mohamed; Loudiy, Aymen; Erkartal, Mustafa; Yilmaz, CagatayElectromagnetic wave (EMW) radiation pollution is getting more severe as result of the advancement of electronic technology. Researching shielding materials with superior EMI (electromagnetic interference) shielding characteristics is therefore crucial. Basalt fibers (BFs) have been an emerging candidate in the fiber-reinforced polymer (FRP) category due to their favorable mechanical and chemical properties, along with being favorites in sustainability and having low production costs. Therefore, due to the rising need for cheaper and efficient alternatives in the EMI shielding industry, the EMI shielding is covered in terms of BF composite materials and their properties in this review, starting with the EMI shielding mechanism and followed by how BF composites affect the EMI properties. This review then covers the post-treatments of BF composites and, finally, the factors of the composites that affect the EMI properties. Moreover, the EMI shielding applications in which BFRPs are used are comprehensively discussed as well. This review aspires to bridge an understanding between EMI shielding as a material property and the BF composites that are developed to aid in the EMI shielding application.Article Citation - WoS: 3Citation - Scopus: 4An In-Depth Investigation of Mg-Zn Metallic Glasses: A First Principles Study(Elsevier, 2018-10) Erkartal, Mustafa; Durandurdu, MuratThe atomic structures, glass forming evolutions, mechanical properties and high pressure behavior of Mg75Zn20Ca5 and Mg60Zn35Ca5 bulk metallic glasses, which are promising candidates for biomedical implants, have been examined by using ab initio molecular dynamics simulations. The pair-distribution function and coordination number analyses show that increasing Zn content in the alloy results in a decrease in several bond distances and an increase in the total coordination number of each species due to the atomic size difference between Mg and Zn atoms. According to the Voronoi tessellation, bond pair and bond angle distribution analyzes, the fivefold geometrical arrangements (pentagonal-bipyramid) are the most predominant in the first coordination shell, indicating the stability of the amorphous states and their dense atomic packing. The most striking result emerged from the calculations of mechanical properties is that an increase of Zn (>= 30%) content in the alloy yields embrittlement in the alloys. Under uniaxial compressions, both compositions undergo structural failure between 6 and 8 GPa. Under hydrostatic pressure, a diminishing in fcc/hcp ordering and an enlargement of the ideal icosahedral ordering may indicate a more disordered structure. In our view, these results represent a good step toward understanding the atomic structures Mg-Zn-Ca bulk metallic glasses.