Publications without Fulltext
Permanent URI for this collectionhttps://hdl.handle.net/20.500.14288/3
Browse
15 results
Search Results
Publication Metadata only Computational simulations of metal–organic frameworks to enhance adsorption applications(John Wiley and Sons Inc, 2024) Department of Chemical and Biological Engineering; Harman, Hilal Dağlar; Gülbalkan, Hasan Can; Aksu, Gökhan Önder; Keskin, Seda; Department of Chemical and Biological Engineering; Graduate School of Sciences and Engineering; College of EngineeringMetal–organic frameworks (MOFs), renowned for their exceptional porosity and crystalline structure, stand at the forefront of gas adsorption and separation applications. Shortly after their discovery through experimental synthesis, computational simulations quickly become an important method in broadening the use of MOFs by offering deep insights into their structural, functional, and performance properties. This review specifically addresses the pivotal role of molecular simulations in enlarging the molecular understanding of MOFs and enhancing their applications, particularly for gas adsorption. After reviewing the historical development and implementation of molecular simulation methods in the field of MOFs, high-throughput computational screening (HTCS) studies used to unlock the potential of MOFs in CO2 capture, CH4 storage, H2 storage, and water harvesting are visited and recent advancements in these adsorption applications are highlighted. The transformative impact of integrating artificial intelligence with HTCS on the prediction of MOFs’ performance and directing the experimental efforts on promising materials is addressed. An outlook on current opportunities and challenges in the field to accelerate the adsorption applications of MOFs is finally provided. © 2024 The Author(s). Advanced Materials published by Wiley-VCH GmbH.Publication Metadata only Novel nanostructured composites of silica aerogels with a metal organic framework(Elsevier, 2013) N/A; N/A; Department of Chemical and Biological Engineering; Department of Chemical and Biological Engineering; Ülker, Zeynep; Eruçar, İlknur; Keskin, Seda; Erkey, Can; PhD Student; PhD Student; Faculty Member; Faculty Member; Department of Chemical and Biological Engineering; Koç University Tüpraş Energy Center (KUTEM) / Koç Üniversitesi Tüpraş Enerji Merkezi (KÜTEM); Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; College of Engineering; 262388; 260094; 40548; 29633Novel nanostructured composites of silica aerogel with Cu-BTC were synthesized using a slightly modified version of the conventional sol-gel method used to synthesize silica aerogels. The composite materials had monolithic structures with blue color consisting of well dispersed microporous domains of Cu-BTC in the mesoporous inorganic silica aerogel network. The Cu-BTC content in the composites ranged from 5 to 30 weight percent and the total surface area of the composites ranged from 1025 to 1138 m(2)/g. The microporosity of the composites increased with the increasing amount of Cu-BTC indicating that the micropores of Cu-BTC were accessible and functional. XRD analysis indicated that Cu-BTC retained its crystal structure in the composite despite being immersed in a solution containing water, ethanol and tetraethylorthosilicate. Additionally, it was observed that increasing Cu-BTC content caused a decrease in the average desorption pore radius with a wider pore size distribution. Nitrogen adsorption isotherms for composites could be predicted using the experimentally obtained pure component isotherm for the silica aerogel, theoretically obtained isotherm for Cu-BTC and the weight fractions of the components within the composite material.Publication Metadata only Site characteristics in metal organic frameworks for gas adsorption(Pergamon-Elsevier Science Ltd, 2014) Department of Chemical and Biological Engineering; Department of Chemical and Biological Engineering; Uzun, Alper; Keskin, Seda; Faculty Member; Faculty Member; Department of Chemical and Biological Engineering; College of Engineering; College of Engineering; 59917; 40548Metal organic frameworks (MOFs) are a new class of nanoporous materials that have many potential advantages over traditional nanoporous materials for several chemical technologies including gas adsorption, catalysis, membrane-based gas separation, sensing, and biomedical devices. Knowledge on the interaction of guest molecules with the MOF surface is required to design and develop these MOF-based processes. In this review, we examine the importance of identification of gas adsorption sites in MOFs using the current state-of-the-art in experiments and computational modeling. This review provides guidelines to design new MOFs with useful surface properties that exhibit desired performances, such as high gas storage capacity, and high gas selectivity. (C) 2013 Elsevier Ltd. All rights reserved.Publication Metadata only Molecular modeling of mof-based mixed matrix membranes(Bentham Science Publ Ltd, 2014) N/A; Department of Chemical and Biological Engineering; Eruçar, İlknur; Keskin, Seda; PhD Student; Faculty Member; Department of Chemical and Biological Engineering; Graduate School of Sciences and Engineering; College of Engineering; 260094; 40548Metal organic framework (MOF)-based mixed matrix membranes (MMMs) have received significant attention in the last couple of years due to their high gas permeabilities and high gas selectivities compared to pure polymeric membranes in various gas separation applications. Computational methods that can predict the gas separation performances of MOF-based MMMs are highly valuable since experimental screening of these MMMs is not practical given the very large number of combination of MOFs and polymers. In this review, molecular modeling methods and theoretical permeation models that have been used to assess the gas separation performance of MOF-based MMMs are discussed; opportunities and challenges in modeling of MOF/polymer membranes are addressed.Publication Metadata only Photocrosslinking of styrene-butadiene-styrene (SBS) networks formed by thiol-ene reactions and their influence on cell survival(IOP Publishing Ltd, 2015) Department of Chemical and Biological Engineering; N/A; Department of Chemical and Biological Engineering; Gidon, Doğan; Aydın, Derya; Kızılel, Seda; Researcher; Researcher; Faculty Member; Department of Chemical and Biological Engineering; College of Engineering; N/A; College of Engineering; Koç University Tüpraş Energy Center (KUTEM) / Koç Üniversitesi Tüpraş Enerji Merkezi (KÜTEM); N/A; N/A; 28376Styrene-butadiene-styrene (SBS) triblock copolymer has been conventionally used as synthetic rubber. However, the potential of SBS for biomedical applications has only been considered in limited earlier reports. Here, we demonstrate an effective approach to designing a photocrosslinked SBS network. Rheological analysis has been conducted for the investigation of the storage modulus of the resultant network. Crosslinked SBS networks were synthesized and characterized through optical and electron microscope imaging. The crosslink density of the network, calculated from swelling experiments, was 643 mol m(-3), where higher swelling in a hydrophobic medium was observed compared to the swelling measured in water. Cell survival analysis with HeLa cells and NIH/3T3 fibroblasts revealed that these networks are non-toxic, and that they could be considered for a variety of biomedical applications.Publication Metadata only Recent advances in computational modeling of MOFs: from molecular simulations to machine learning(Elsevier B.V., 2023) N/A; N/A; N/A; N/A; Department of Chemical and Biological Engineering; Demir, Hakan; Harman, Hilal Dağlar; Gülbalkan, Hasan Can; Aksu, Gökhan Önder; Keskin, Seda; Other; PhD Student; PhD Student; PhD Student; Faculty Member; Department of Chemical and Biological Engineering; N/A; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A; N/A; N/A; 40548The reticular chemistry of metal–organic frameworks (MOFs) allows for the generation of an almost boundless number of materials some of which can be a substitute for the traditionally used porous materials in various fields including gas storage and separation, catalysis, drug storage and delivery. The number of MOFs and their potential applications are growing so quickly that, when novel MOFs are synthesized, testing them for all possible applications is not practical. High-throughput computational screening approaches based on molecular simulations of materials have been widely used to investigate MOFs and identify the optimal MOFs for a specific application. Despite the growing computational resources, given the enormous MOF material space, computational identification of promising MOFs requires more efficient approaches in terms of time and effort. Leveraging data-driven science techniques can offer key benefits such as accelerated MOF design and discovery pathways via the establishment of machine learning (ML) models and interpretation of complex structure-performance relationships that can reach beyond expert intuition. In this review, we present key scientific breakthroughs that propelled computational modeling of MOFs and discuss the state-of-the-art approaches extending from molecular simulations to ML algorithms. Finally, we provide our perspective on the potential opportunities and challenges for the future of big data-driven MOF design and discovery. © 2023 The AuthorsPublication Metadata only Application of the numerical fractionation approach to the design of biofunctional PEG hydrogel membranes(Wiley-V C H Verlag Gmbh, 2012) N/A; Department of Chemical and Biological Engineering; Department of Chemical and Biological Engineering; Kızılel, Rıza; Kızılel, Seda; Researcher; Faculty Member; Department of Chemical and Biological Engineering; College of Engineering; College of Engineering; 114475; 28376A mathematical model is described for surface-initiated photopolymerization of PEG-DA forming crosslinked biofunctional PEG hydrogel membranes based on the NF technique. The model includes an additional monomer with biological functionality, which is a common experimental strategy for the design of ECM mimics in tissue engineering in order to direct signaling pathways, and considers concentration-dependent VP propagation and reaction diffusion termination. The influence of these features on the crosslink density of the soluble and gel phases, the progression through gelation, sol/gel fraction, and molecular weight distribution of biofunctional PEG hydrogel are studied using the NF model. This model may be useful for specific applications of tissue engineering.Publication Metadata only Demixing pressures of hydroxy-terminated poly(dimethylsiloxane)-carbon dioxide binary mixtures at 313.2 K, 323.2 K and 333.2 K(Elsevier Science Bv, 2014) N/A; Department of Chemical and Biological Engineering; Şanlı, Deniz; Erkey, Can; Researcher; Faculty Member; Department of Chemical and Biological Engineering; Koç University Tüpraş Energy Center (KUTEM) / Koç Üniversitesi Tüpraş Enerji Merkezi (KÜTEM); Graduate School of Sciences and Engineering; College of Engineering; N/A; 29633The phase behavior of PDMS(OH)-CO2 binary mixtures was investigated. Two different molecular weight PDMS(OH) were utilized and the demixing pressures were determined at three temperatures for a wide composition range. Both of these polymers were found to form miscible mixtures with CO2 at all compositions at pressures lower than 31 MPa in the temperature range 313.2-333.2 K. Depending on the composition of the binary mixtures, two types of phase separation was observed during depressurization; the bubble point and the cloud point. In addition, at specific weight fractions a color change was also observed which was attributed to the mixture critical point. The demixing pressures were observed to increase with temperature and decrease with increasing polymer weight fraction. In addition, higher demixing pressures were obtained for the higher molecular weight polymer mixtures. The bubble point data were modeled by using Sanchez-Lacombe equation of state (SLEoS) and the binary interaction parameters were regressed at the studied temperatures. It was observed that the binary interaction parameters decreased with increasing temperature.Publication Metadata only Visible-light-induced synthesis of pH-responsive composite hydrogels for controlled delivery of the anticonvulsant drug pregabalin(Elsevier Sci Ltd, 2015) N/A; Department of Chemical and Biological Engineering; Department of Chemical and Biological Engineering; Çevik, Özlem; Gidon, Doğan; Kızılel, Seda; N/A; Undergraduate; Faculty Member; Department of Chemical and Biological Engineering; N/A; College of Engineering; College of Engineering; N/A; N/A; 28376We report here a novel method for the synthesis of a pH-responsive composite using visible light. Formation of the pH-responsive layer is based on poly(methacrylic acid-g-ethylene glycol) as the macromer, eosin Y as the photoinitiator and triethanolamine as the co-initiator. The hydrogel was functionalized with hydrophobic domains through incorporation of crosslinked styrene-butadiene-styrene (SBS) copolymer into the pH-responsive prepolymer. Swelling ratios were decreased with the addition of SBS, and resulted in high hydrogel crosslink density. The composite allowed for controlled release of an anticonvulsant model drug, pregabalin, under neutral pH condition and the release was analyzed to describe the mode of transport through the network. In vitro human fibroblast survival assay and in vivo rabbit implantation experiments demonstrated that this hybrid network is not toxic and has desirable biocompatibility properties. This is the first report about the synthesis of a pH-responsive network incorporating crosslinked SBS synthesized under visible light. The approach for multifunctional membranes could allow the incorporation of molecules with specific functionalities so that sequential molecule delivery in response to specific stimuli could be achieved. (C) 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.Publication Metadata only Multiscale dynamics of lipid vesicles in polymeric microenvironment(Mdpi, 2022) N/A; N/A; N/A; N/A; N/A; Department of Electrical and Electronics Engineering; Department of Chemical and Biological Engineering; Department of Chemical and Biological Engineering; Karaz, Selcan; Han, Mertcan; Akay, Gizem; Önal, Asım; Nizamoğlu, Sedat; Kızılel, Seda; Şenses, Erkan; Master Student; Master Student; PhD Student; PhD Student; Faculty Member; Faculty Member; Faculty Member; Department of Electrical and Electronics Engineering; Department of Chemical and Biological Engineering; Koç University Surface Science and Technology Center (KUYTAM) / Koç Üniversitesi Yüzey Teknolojileri Araştırmaları Merkezi (KUYTAM); Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; College of Engineering; College of Engineering; N/A; N/A; N/A; N/A; 130295; 28376; 280298Understanding dynamic and complex interaction of biological membranes with extracellular matrices plays a crucial role in controlling a variety of cell behavior and functions, from cell adhesion and growth to signaling and differentiation. Tremendous interest in tissue engineering has made it possible to design polymeric scaffolds mimicking the topology and mechanical properties of the native extracellular microenvironment; however, A fundamental question remains unanswered: that is, how the viscoelastic extracellular environment modifies the hierarchical dynamics of lipid membranes. in this work, we used aqueous solutions of poly(ethylene glycol) (PEG) with different molecular weights to mimic the viscous medium of cells and nearly monodisperse unilamellar DMPC/DMPG liposomes as a membrane model. Using small-angle X-ray scattering (SaXS), dynamic light scattering, temperature-modulated differential scanning calorimetry, bulk rheology, and fluorescence lifetime spectroscopy, we investigated the structural phase map and multiscale dynamics of the liposome-polymer mixtures. the results suggest an unprecedented dynamic coupling between polymer chains and phospholipid bilayers at different length/time scales. the microviscosity of the lipid bilayers is directly influenced by the relaxation of the whole chain, resulting in accelerated dynamics of lipids within the bilayers in the case of short chains compared to the polymer-free liposome case. at the macroscopic level, the gel-to-fluid transition of the bilayers results in a remarkable thermal-stiffening behavior of polymer-liposome solutions that can be modified by the concentration of the liposomes and the polymer chain length.