Dokument: Thermoresponsive Core-Shell Microgels as Model System for Soft Colloids in Crowded Environments: Insights into the Phase Behavior via Small Angle X-ray Scattering and Optical Spectroscopy
| Titel: | Thermoresponsive Core-Shell Microgels as Model System for Soft Colloids in Crowded Environments: Insights into the Phase Behavior via Small Angle X-ray Scattering and Optical Spectroscopy | |||||||
| Weiterer Titel: | Thermoresponsive Kern-Schale Mikrogele als Modell System für weiche Kolloide in dichten Packungen: Einblicke in das Phasen Verhalten mittels Kleinwinkel-Röntgenstreuung und optischer Spektroskopie | |||||||
| URL für Lesezeichen: | https://docserv.uni-duesseldorf.de/servlets/DocumentServlet?id=64831 | |||||||
| URN (NBN): | urn:nbn:de:hbz:061-20240209-141001-9 | |||||||
| Kollektion: | Dissertationen | |||||||
| Sprache: | Englisch | |||||||
| Dokumententyp: | Wissenschaftliche Abschlussarbeiten » Dissertation | |||||||
| Medientyp: | Text | |||||||
| Autor: | Hildebrandt, Marco [Autor] | |||||||
| Dateien: |
| |||||||
| Beitragende: | Prof. Dr. Karg, Matthias [Gutachter] Prof. Dr. Peter R. Lang [Gutachter] | |||||||
| Stichwörter: | Microgels, X-ray scattering, colloidal crystals, phase behavior | |||||||
| Dewey Dezimal-Klassifikation: | 500 Naturwissenschaften und Mathematik » 540 Chemie | |||||||
| Beschreibung: | In this thesis, core shell microgels were synthesized and used to investigate soft colloids in dense packings via small angle X-ray scattering (SAXS). The core-shell microgels consist of an inorganic core made from gold or silica and a thermoresponsive poly N isopropylacrylamide hydrogel shell which provides in situ control over the volume fraction of the particles in dispersion. Via the scattering intensity of the cores in SAXS, particle number concentrations became accessible, which is otherwise hard to achieve for soft and deformable systems like microgels.
Core shell microgels in the dilute state were characterized in great detail by electron microscopy and various scattering techniques like temperature-dependent dynamic light scattering and small angle X-ray or neutron scattering. Dispersions of core-shell microgels in dense packings, forming crystalline structures, were investigated by synchrotron SAXS in order to receive information about the morphology, size and the structure of the self-assembled microgels in crowded environments. The recorded scattering profiles from silica core shell microgels exhibited multiple diffraction orders of narrow Bragg peaks which indicated a high spatial correlation of microgels forming colloidal crystals. The photonic properties of the colloidal crystals were used to follow the phase transition of the core-shell microgels between the crystalline and fluid phase by temperature dependent optical spectroscopy. In addition, the influence of electrostatics on the phase behavior of the core shell microgels could be studied by the screening of charges, exhibited by the microgels, due to an alteration in the ionic strength of the dispersion. The effect of charge screening on crystalline and fluid samples of microgels was studied by synchrotron SAXS and the influence on the phase behavior was further investigated by temperature dependent optical spectroscopy. | |||||||
| Lizenz: |  Dieses Werk ist lizenziert unter einer Creative Commons Namensnennung 4.0 International Lizenz | |||||||
| Fachbereich / Einrichtung: | Mathematisch- Naturwissenschaftliche Fakultät » WE Chemie » Physikalische Chemie und Elektrochemie | |||||||
| Dokument erstellt am: | 09.02.2024 | |||||||
| Dateien geändert am: | 09.02.2024 | |||||||
| Promotionsantrag am: | 19.10.2023 | |||||||
| Datum der Promotion: | 25.01.2024 |
