dc.contributor.advisor | Vana, Philipp Prof. Dr. | de |
dc.contributor.author | Förster, Nadja | de |
dc.date.accessioned | 2012-11-21T15:44:10Z | de |
dc.date.accessioned | 2013-01-18T10:38:44Z | de |
dc.date.available | 2013-01-30T23:51:24Z | de |
dc.date.issued | 2012-11-21 | de |
dc.identifier.uri | http://hdl.handle.net/11858/00-1735-0000-000D-F054-D | de |
dc.identifier.uri | http://dx.doi.org/10.53846/goediss-2180 | |
dc.description.abstract | In diesem Projekt wurde die Darstellung
nano-skalierter und monomolekularer Objekte untersucht, die als
Transporter für andere Moleküle genutzt werden können. Solche
Nanotransporter werden im Medikamententransport, im Feld der
Katalyse oder als Template für Hybridmaterialien verwendet. Als
runde Grundlage für diese Nanotransporter wurden amphiphile,
sternförmige Diblockcopolymere verwendet. Sternpolymere besitzen
einen zentralen Knotenpunkt, der von sechs amphiphilen Armen
umgeben ist. Sternpolymere erfüllen die erforderten
Voraussetzungen: Sie sind unimolekular, gleich groß und
monodispers, chemisch stabil in den verschiedenen Syntheseschritten
und einfach zu synthetisieren mittels RAFT-Polymerisation. Im
Gegensatz zu selbstorganisierenden Systemen, wie Mizellen, ist
Stabilität in verschiedenen Lösemitteln und Verdünnungen, bei
verschiedenen pH-Werten und Temperaturen sowie in Gegenwart von
Ionen gegeben. Die Arme der Sternpolymere können für verschiedenen
Anwendungen angepasst und modifiziert werden, da RAFT vielseitig
bezüglich der verwendeten Monomere und Lösungsmittel ist, was eine
definierte Synthese der Polymere bezüglich Größe und
Zusammensetzung ermöglicht Durch Vernetzung der Arme wird die Hülle
des Transporters geschlossen. Nach Entfernen des RAFT-Kerns kann
die gewünschte Substanz im Innern des Transporters eingelagert
werden. | de |
dc.format.mimetype | application/pdf | de |
dc.language.iso | eng | de |
dc.rights.uri | http://creativecommons.org/licenses/by-nc-nd/3.0/ | de |
dc.title | Nano-Carrier Synthesis via Z-RAFT Star Polymerisation | de |
dc.type | doctoralThesis | de |
dc.title.translated | Nanotransportersynthese mittels Z-RAFT-Sternpolymerisation | de |
dc.contributor.referee | Vana, Philipp Prof. Dr. | de |
dc.date.examination | 2012-10-18 | de |
dc.subject.dnb | 540 Chemie | de |
dc.subject.gok | SWE 800 | de |
dc.subject.gok | SWE 200 | de |
dc.subject.gok | SWE 250 | de |
dc.description.abstracteng | In this project the establishment of
nano-scaled and monomolecular objects working as carrier system was
investigated. Such nano-carriers find application in drug delivery,
catalysis or as templates for hybrid nanomaterials. As globular
platform for these nano-carriers, amphiphilic diblock star-shaped
copolymers were used. Star polymers containing a central core
surrounded by radiating arms provide various requirements requested
to yield the proposed nano-carriers: they are unimolecular, equal
sized and monodispersed, chemically stable in different
modification steps and easily synthesised by means of radical
Reversible Addition-Fragmentation Transfer (RAFT) polymerisation.
In contrary to self-assembling systems, e.g. micelles, stability in
various solvents and dilution, at different pH-values and
temperatures as well as in the presence of charges is given. The
arms of the polymer stars can be tuned for the different fields of
application as RAFT is versatile regarding monomers and solvents
and enables the defined synthesis of polymers in size and
composition. By cross-linking the arms, the carrier's shell should
be formed. Removal of the RAFT-template enables the storage of the
desired compounds within the shell. Within this project RAFT-agents
with six RAFT-groups represented the template for the star polymer.
The number of RAFT-units corresponded to the number of arms the
star consisted of. The Z-group approach was applied which enabled
the arms to grow from the centre and thus prevent star-star
coupling. To form the carrier's shell, [2+2]-cycloaddition by
UV-irradiation was chosen. Therefore the outer block of the diblock
copolymer arms had to consist of units of a basic monomer and a
monomer carrying a unit which undergoes a [2+2]-cycloaddition. At
first a suitable polymerisation system had to be found: monomers
based on N-alkyl-3,4-dimethylmaleimid (DMI), cinnamic acid (CA) and
courmarins were tested in firstly in RAFT copolymerisations with
n-butylacrylate (BA), N-isopropylacrylamide (NIPAam),
methylmethacrylate (MMA) and methylacrylate (MA). It was found that
BA and NIPAam along with the DMI-based monomer 1.1 yield copolymers
with well-defined molecular weight and narrow polydispersities. The
existence of six-armed polymer stars could be proven by
AFM-measurements. The composition of the polymers and the
copolymerisation parameters for both systems were determined by
NMR-spectroscopy indicating that a gradient polymer was formed. Two
kinds of amphiphillic star polymers were investigated: stars with a
hydrophobic corona made of p(BA-co-1.1) and a hydrophilic
pNIPAam-core and the reversed case with a hydrophilic shell.
Different UV-lamp systems were tested for cross-linking reactions
induced by UV-irradiation. The success of the reaction was
monitored by SEC-measurements. It was found that the RAFT centres
of the star polymers were destroyed by energy entries above 150 W
resulting in linear polymers, i.e. loose arms. Lower irradiation
energies yielded star polymers with a closed shell. As a last step
the removal of the RAFT-template by aminolysis was investigated and
verified by SEC-measurements. | de |
dc.contributor.coReferee | Buback, Michael Prof. Dr. | de |
dc.subject.topic | Chemistry | de |
dc.subject.ger | RAFT-Polymerisation | de |
dc.subject.ger | Sternpolymere | de |
dc.subject.ger | Nanotransporter | de |
dc.subject.ger | UV-Vernetzung | de |
dc.subject.ger | UV-induzierte [2+2]-cycloaddition | de |
dc.subject.ger | amphiphile Polymere | de |
dc.subject.eng | RAFT-Polymerisation | de |
dc.subject.eng | star polymers | de |
dc.subject.eng | nano-carrier | de |
dc.subject.eng | UV-cross linking | de |
dc.subject.eng | UV-induced [2+2]-cycloaddition | de |
dc.subject.eng | amphiphilic polymers | de |
dc.subject.bk | 35.80 | de |
dc.identifier.urn | urn:nbn:de:gbv:7-webdoc-3804-5 | de |
dc.identifier.purl | webdoc-3804 | de |
dc.affiliation.institute | Fakultät für Chemie | de |
dc.identifier.ppn | 737898739 | de |