Physically cross-linked polymers through anion recognition

dc.contributor.advisor Aydoğan, Abdullah
dc.contributor.author Odabaş, Ayşe
dc.contributor.authorID 740869
dc.contributor.department Chemistry Programme
dc.date.accessioned 2025-01-31T13:01:52Z
dc.date.available 2025-01-31T13:01:52Z
dc.date.issued 2022
dc.description Thesis (M.Sc.) -- Istanbul Technical University, Graduate School, 2022
dc.description.abstract Supramolecular chemistry revolves around relatively small molecular systems that can self-assemble with the assist of highly directional intermolecular interactions such as metal coordination, host guest inclusion, hydrogen bonds, π-π stacking and supported with non-directional ones such as van der Waals forces, hydrophobic interactions. Reversible nature of these systems allows for shape memory, self-healing, and stimuli responsiveness. Self-assembly process of supramolecular systems can be manipulated to be stimuli responsive to UV light, pH and temperature and concentration variations. Designing materials with self-assembling properties creates opportunities for wider application of low molecular weight monomers and even covalently bonded polymer chains. Some of the application areas include drug-release systems, ion sensors, bio-compatible materials, thermo-responsive adhesives, and coatings. Main caveat of this dynamic nature and mobility can result in materials with low thermodynamic stability but it can be improved via utilizing various secondary interactions simultaneously. A Calix[4]pyrrole skeleton consists of four pyrrole rings bridged by methylene at 2, 5 positions and functionalized by total of 8 methyl substitutions at meso-rim to form a non-conjugated macrocyclic structure. It can switch between four possible conformations, 1,3 alternate, 1,2 alternate, partial cone and cone. Cone conformation provides the most ideal environment for ion binding as quadruple directional hydrogen disposition on nitrogen atoms enables a relatively attractive site towards anions, neutral substrates, and anion-cation pairs. Supramolecular polymers with host-guest interactions have seen enthusiastic interest on cationic guest species and anionic congeners have recieved relatively less attention. Supramolecular polymerization can be self-induced via hydrogen bonding and mechanical properties can be further reinforced by pseudo cross-linking in the form of host-guest complexation with anionic species, which might allow a construct similar to polymer gel networks. Utilizing the same principle on polymer chains may provide the formation of physical cross-linking between polymer chains, resulting in the construction of supramolecular polymer gels. This study has two focuses, both stemming from the utilization of anion recognition chemistry of calix[4]pyrroles to design reversibly cross-linked materials in organic media. A bis-ureido pyrimidinone functionalized calix[4]pyrrole (Bis-UPyC4P) unit and a bis-carboxylate ((TBA)2Terepthalate) were used, as host and guest moieties respectively, for supramolecular networks. Another approach was taken with calix[4]pyrrole units as a part of a polyurethane polymer backbone (P-C4P) and a bis-carboxylate ((TBA)2Suberate) to form supramolecular polymer gel networks. P-C4P was also utilized in liquid-liquid extraction studies of anions. Both Bis-UPyC4P and P-C4P materials have shown increased viscosity in the presence of bis carboxylate salts as well as thermo-responsiveness. P-C4P was relatively successful at extraction studies. These systems were analyzed by NMR spectroscopy, viscosity and conductivity measurements, UV-VIS spectroscopy, and rheological analyses.
dc.description.degree M.Sc.
dc.identifier.uri http://hdl.handle.net/11527/26323
dc.language.iso en
dc.publisher Graduate School
dc.sdg.type Goal 9: Industry, Innovation and Infrastructure
dc.subject polyurethane
dc.subject Calixpyrrole
dc.subject Anions
dc.subject Chemistry
dc.title Physically cross-linked polymers through anion recognition
dc.title.alternative Anyon tanınması ile fiziksel olarak çapraz bağlanmış polimerler
dc.type Master Thesis
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