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Switchable Surfaces: Mono- and Multilayers of Stimuli-Responsive Supramolecules on Solid Supports
- Rotaxanes are mechanically interlocked molecules (MIMs) that are considered to be excellent prototypes for the development of molecular machines. They comprise a discrete number of molecules that are bound to each other via non-covalent interactions. Mechanically interlocked means that a covalent bond must be broken in order to separate the molecules from another. If the rotaxanes are furthermore provided with different binding sites, they can perform a con-formational change and thus a nanoscopic movement by the application of an external stimu-lus. However, this movement is not directed in solution and a macroscopic effect is therefore, if at all, very difficult to realize. The integration of rotaxanes into a reference system by, for example, the immobilization on a surface is regarded as a promising approach to convert the generated nanoscopic motion into a macroscopic effect. The present work describes the immobilization of chloride-switchable rotaxanes onto surfaces using aRotaxanes are mechanically interlocked molecules (MIMs) that are considered to be excellent prototypes for the development of molecular machines. They comprise a discrete number of molecules that are bound to each other via non-covalent interactions. Mechanically interlocked means that a covalent bond must be broken in order to separate the molecules from another. If the rotaxanes are furthermore provided with different binding sites, they can perform a con-formational change and thus a nanoscopic movement by the application of an external stimu-lus. However, this movement is not directed in solution and a macroscopic effect is therefore, if at all, very difficult to realize. The integration of rotaxanes into a reference system by, for example, the immobilization on a surface is regarded as a promising approach to convert the generated nanoscopic motion into a macroscopic effect. The present work describes the immobilization of chloride-switchable rotaxanes onto surfaces using a variety of methods. In detail, the applied methods are the metal-mediated layer-by-layer (LbL) self-assembly and the covalent deposition using click chemistry, which can be con-sidered as separate approaches. Before the rotaxanes were immobilized, the deposition meth-ods were first established and gradually improved on the basis of earlier results by using dif-ferent macrocycle and guest molecules. Various template layers – so-called self-assembled monolayers (SAMs) – were used. These are terminated with pyridine or terpyridine for the metal-induced LbL deposition. Azide-terminated SAMs are used for the covalent deposition. In the course of that, the following objectives were achieved: The deposition of diterpyridin functionalized macrocycles in multilayers with a preferential orientation was investigated and verified by transmission-UV/Vis, X-ray photoelectron spectroscopy (XPS) as well as near edge X-ray absorption fine structure (NEXAFS). In order to produce the multilayer, metal-ions and macrocycles were alternately deposited onto various SAMs. To enable further process control for the LbL deposition, Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) has been extended by use of Principal Component Analysis (PCA) which is capable of analyzing even very small changes in the deposition procedure. By using two different macrocycles and four metals, a mixed multilayer was fabricated that can be programmed by its deposition sequence. The treatment of the multilayers with appropriate guest molecules showed that they are on one hand addressable to the lowest layer by an external stimulus and that they are on the other hand able to incorporate a relatively large amount of the guest. Additionally, the covalently deposited supramolecules are also able to bind guests and to adapt to their structures. In both cases, the reversibility could be shown by appropriate experiments. Finally, the introduction of pyridine-functionalized nanoparticles into the multilayers led to a higher guest uptake, which can be explained by the reduction of the macrocycle-order due to the uneven surface of the nanoparticles.…
Autor*innen: | Thomas Heinrich |
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Dokumenttyp: | Dissertation |
Veröffentlichungsform: | Graue Literatur |
Sprache: | Englisch |
Jahr der Erstveröffentlichung: | 2016 |
Veröffentlichende Institution: | Bundesanstalt für Materialforschung und -prüfung (BAM) |
Titel verleihende Institution: | Freie Universität Berlin, Fachbereich Biologie, Chemie, Pharmazie |
Gutachter*innen: | Christoph Schalley, Rainer Haag |
Datum der Abschlussprüfung: | 11.02.2016 |
Verlag: | Freie Unversität |
Verlagsort: | Berlin |
Erste Seite: | 1 |
Letzte Seite: | 139 |
DDC-Klassifikation: | Naturwissenschaften und Mathematik / Chemie / Analytische Chemie |
Freie Schlagwörter: | Layer-by-layer deposition; NEXAFS; Switchable rotaxane; ToF SIMS; XPS |
URN: | urn:nbn:de:kobv:188-fudissthesis000000103658-0 |
Verfügbarkeit des Dokuments: | Datei für die Öffentlichkeit verfügbar ("Open Access") |
Lizenz (Deutsch): | Allgemeines Deutsches Urheberrecht |
Datum der Freischaltung: | 03.04.2017 |
Referierte Publikation: | Nein |
Schriftenreihen ohne Nummerierung: | BAM Dissertationen ohne Nummerierung |