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Novel synthetic approaches for fabrication of polymer brushes on gold surfaces via Raft polymerization: A new era for gold modification

dc.contributor.advisorVana, Philipp Prof. Dr.
dc.contributor.authorCatli, Candan
dc.date.accessioned2018-02-14T14:00:39Z
dc.date.available2018-02-14T14:00:39Z
dc.date.issued2018-02-14
dc.identifier.urihttp://hdl.handle.net/11858/00-1735-0000-002E-E353-2
dc.identifier.urihttp://dx.doi.org/10.53846/goediss-6726
dc.language.isoengde
dc.publisherNiedersächsische Staats- und Universitätsbibliothek Göttingende
dc.rights.urihttp://creativecommons.org/licenses/by-nc-nd/4.0/
dc.subject.ddc540de
dc.titleNovel synthetic approaches for fabrication of polymer brushes on gold surfaces via Raft polymerization: A new era for gold modificationde
dc.typedoctoralThesisde
dc.contributor.refereeEnderlein, Jörg Prof. Dr.
dc.date.examination2017-02-15
dc.description.abstractengNanobiotechnology is an important branch of nanotechnology, which has been dramatically developed for creating functional nanoscale materials for various biomedical applications. The past few decades have witnessed significant advances in the development of various functionalized surfaces for applications in a wide range of fields such as chemistry, biology, pharmacy and physics. There has recently been extensive research to modify gold surfaces, thereby opening up opportunities to enhance breadth of their applicability. Recently developed methods have allowed the modification of gold nanoparticles with suitable functionalizing agents, facilitate their applications in different areas such as chemical and biological sensing, imaging labelling, delivering, heating and biomedical applications such as cancer diagnostics and therapy, drug delivery, gene delivery, DNA and RNA analysis, antibacterial agent, vaccine preparation, brain implants, artificial skin and improving electrical signaling in the heart. Apart from gold nanoparticle surfaces, there are various blood contacting biomedical devices used for applications such as heart valves, vascular grafts, stents, in vivo biosensors etc. The lack of hemo compatibility is main problem of cardiovascular and other blood contacting medical devices. Congestion of small diameter vascular grafts and failure of blood contacting biosensors due to thrombus formation on device surface might be counted as some examples for this hemo compatibility problem. Non specific protein adsorption can decrease device performance, such as in the case of in vivo biosensor and stent surfaces. For this reason, improvement of anticoagulant devices or drugs is required for long term applications. Surface modification is an essential process in biotechnological fields such as tissue engineering, biosensors, or implant manufacturing. Covalently bound polymer films offer an efficient and convenient way of modifying physicochemical characteristics of material surfaces used for various applications such as stabilization of colloidal particles, non-fouling coatings, and responsive films for sensors. Sofar, several strategies were developed for modification of device surfaces with an aim of reducing non-specific protein adsorbtion. Synthetic polymers serve as excellent candidates for surface modification because of their tunable mechanical properties, the variability of film thickness, degree of functionality and because of the potential multifunctional stimuli responsivity. Furthermore, synthetic polymers and their hybrids with biological molecules have been widely used in biotechnology, biomedical, and pharmaceutical technologies. In terms of the role of nanoscale properties in applications, it is important to tailor the properties of polymers at molecular level to fulfill the performance criteria better for any given application. The design requirements of polymers vary widely according to the application. The key properties for various applications can be counted as the molecular weight, molecular architecture, composition and chemical functionality. The uniformity in these key properties is mandatory for most biological applications of polymers (e.g. biomaterial surfaces), as it enables the performance to be correlated with structure. Among the variety of techniques that allow the formation of polymer thin films for surface modification, polymer brushes have gained special attention along the past decades due to their unique structures in combination with the possibility offered by controlled / “living” radical polymerization techniques (CLRP) to generate polymeric thin films with precisely controlled thickness, composition and architecture. Polymer brushes can be defined as an assembly of polymer chains which are tethered by one ends to a surface. Despite their interesting properties and the numerous reports describing synthetic pathways of polymer brushes via different CLRP techniques, polymer brush formation via Reversible Addition Fragmentation Chain Transfer (RAFT) polymerization technique has received little attention so far. RAFT polymerization is the most versatile platform for controlled synthesis of polymers for biological applications, with respect to monomer types and reaction conditions. When it comes to polymer brush formation on gold planar surfaces via RAFT technique, there has been a few studies in literature. This thesis describes how RAFT polymerization technique is successfully adapted onto gold surfaces with an aim of construction of dense polymer brush layers. So far, the privileged way to tune the desired features, functionalities of a surface has been the growth of tethered polymer chains by the combination of a CRP technique with “grafting from” approach. However, this approach is experimentally rather complex as it involves multi-step synthetic procedures. With this background in mind, the main objective of this thesis work was to develop novel Raft based synthetic approaches for fabrication of polymer brushes with different architectures on gold surface. The interest to develop new synthetic strategies, which are relatively easier than multi-step procedures in literature used for synthesis of brushes, lies in the possibility of utilization of these novel straightforward techniques for the design and production of novel biomaterials used for advanced biomedical applications. The originality of this thesis work stems from the fact that the chemisorption tendency of raft agents toward gold and the specific mechanistic principles of RAFT, which allows for various synthetic strategies of performing surface-confined RAFT polymerizations, were successfully combined in order to develop novel straight forward pathways for synthesis of polymer brushes with complex topologies on gold.de
dc.contributor.coRefereeSamwer, Konrad Prof. Dr.
dc.contributor.thirdRefereeZippelius, Annette Prof. Dr.
dc.subject.engReversible addition fragmentation chain transferde
dc.subject.engRaft polymerizationde
dc.subject.engPolymer brushesde
dc.subject.engStar polymerde
dc.subject.engControlled Radical Polymerizationde
dc.subject.engSynthesis of polymer brushes via Raft polymerizationde
dc.subject.enggrafting fromde
dc.identifier.urnurn:nbn:de:gbv:7-11858/00-1735-0000-002E-E353-2-3
dc.affiliation.instituteFakultät für Chemiede
dc.subject.gokfullChemie  (PPN62138352X)de
dc.identifier.ppn1013981006


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