@phdthesis{Goerl2015,
  author    = {G{\"o}rl, Daniel},
  title     = {Hydrophobe Effekte bolaamphiphiler Rylenbisimide},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-123172},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2015},
  abstract  = {Die Selbstorganisation von amphiphilen Molek{\"u}len z{\"a}hlt zu den am intensivsten bearbeiteten Forschungsgebieten der Supramolekularen Chemie. Die faszinierenden supramolekularen Architekturen der Natur zeigen eindrucksvoll, wie neuartige Funktionen durch das Zusammenspiel wohl-definierter Molek{\"u}lensembles in einer w{\"a}ssrigen Umgebung entstehen. Es ist bekannt, dass der hydrophobe Effekt dabei eine entscheidende Rolle in der Selbstorganisation spielt und somit die Funktion eines Systems wesentlich bestimmt. Obwohl die Komplexit{\"a}t der bekannten Beispiele aus der Natur unerreicht ist, wurden in den letzten Jahren unz{\"a}hlige k{\"u}nstliche supramolekulare Architekturen basierend auf amphiphilen Molek{\"u}len erschaffen, mit vielf{\"a}ltigen Anwendungsm{\"o}glichkeiten an der Schnittstelle von Chemie, Biologie und Physik. Darunter er{\"o}ffnen insbesondere amphiphile π-konjugierte Systeme einen einfachen Zugang zu vielf{\"a}ltigen Strukturen, da im w{\"a}ssrigen Medium starke π-π-Wechselwirkungen als strukturbildendes Element ausgenutzt werden k{\"o}nnen. Vor allem wegen vielversprechender Anwendungsm{\"o}glichkeiten spiegelt sich die Selbstorganisation solcher Systeme in einem hohen Forschungsinteresse wider. Dennoch ist das Wirken des hydrophoben Effekts in der Selbstassemblierung amphiphiler π-konjugierter Molek{\"u}le weitgehend unverstanden. Die vorliegende Arbeit befasste sich daher mit der Frage, welche physikochemischen Grundprinzipien die Bildung von supramolekularen Polymeren basierend auf amphiphilen π-konjugierten Molek{\"u}len in Wasser steuern und wie der hydrophobe Effekt die Funktionalit{\"a}t solcher Strukturen beeinflusst. Bolaamphiphile Perylenbisimide (PBIs) und Naphthalinbisimide (NBIs) erwiesen sich dabei f{\"u}r das Molek{\"u}ldesign als besonders geeignet, weil sie vergleichsweise einfach dargestellt werden k{\"o}nnen, ihre hohe Symmetrie weniger komplexe Assoziationsprozesse begr{\"u}ndet und die Untersuchung ihrer Selbstassemblierung im w{\"a}ssrigen Medium weiterhin einen Vergleich erlaubt, wie sich der hydrophobe Effekt bez{\"u}glich unterschiedlich großen π-Systemen auswirkt. Es konnte gezeigt werden, dass OEG-basierte Rylenbisimide unter bestimmten strukturgeometrischen Voraussetzungen eine entropiegetriebene Aggregation aufweisen, wenn die Freisetzung von Wassermolek{\"u}len aus einer wohl-definierten Hydrath{\"u}lle ausreicht, um den Enthalpiegewinn aus den im w{\"a}ssrigen Medium verst{\"a}rkten Dispersionswechselwirkungen zwischen den π-Fl{\"a}chen zu {\"u}bertreffen. Im vorliegenden Fall wurde dies durch das Pinsel-Strukturmotiv der symmetrisch angebrachten Imidsubstituenten erreicht, f{\"u}r die sich damit einhergehend eine g{\"a}nzlich andere Temperaturabh{\"a}ngigkeit beobachten ließ und somit eine g{\"a}nzlich andere Funktionalit{\"a}t, als man sie aus organischen L{\"o}sungsmitteln kennt. Wasser als L{\"o}sungsmittel f{\"u}hrt also nicht nur zu einer signifikanten Bindungsverst{\"a}rkung, sondern {\"o}ffnet Zugang zu supramolekularen Systemen mit neuartigen Funktionen. Die entropiegetriebene Freisetzung von Wassermolek{\"u}len konnte daher im Rahmen dieser Arbeit ausgenutzt werden, um gleichzeitig die intrinsische Ordnung im π-Stapel von PBIs zu erh{\"o}hen, was anhand eines temperatursensorischen Hydrogels anschaulich demonstriert wurde. Dar{\"u}ber hinaus stellte sich heraus, dass Wasser ein geeignetes L{\"o}sungsmittel zur Darstellung supramolekularer Kompositmaterialien ist. Wie anhand sich instantan bildender Co-Aggregate gezeigt wurde, ist die entropiegetriebene Assemblierung der entscheidende Faktor zur Darstellung von komplexeren supramolekularen Strukturen, die {\"u}berdies einen Schritt hin zu den hochkomplexen multimolekularen Anordnungen der Natur darstellen.},
  subject      = {Selbstorganisation},
  language  = {de}
}
@phdthesis{Rest2015,
  author    = {Rest, Christina},
  title     = {Self-assembly of amphiphilic oligo(phenylene ethynylene)-based (bi)pyridine ligands and their Pt(II) and Pd(II) complexes},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-133248},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2015},
  abstract  = {The presented work in the field of supramolecular chemistry describes the synthesis and detailed investigation of (bi)pyridine-based oligo(phenylene ethynylene) (OPE) amphiphiles, decorated with terminal glycol chains. The metal-ligating property of these molecules could be exploited to coordinate to Pd(II) and Pt(II) metal ions, respectively, resulting in the creation of novel metallosupramolecular π-amphiphiles of square-planar geometry. The focus of the presented studies is on the self-assembly behaviour of the OPE ligands and their corresponding metal complexes in polar and aqueous environment. In this way, the underlying aggregation mechanism (isodesmic or cooperative) is revealed and the influence of various factors on the self-assembly process in supramolecular systems is elucidated. In this regard, the effect of the molecular design of the ligand, the coordination to a metal centre as well as the surrounding medium, the pH value and temperature is investigated.},
  subject      = {Supramolekulare Chemie},
  language  = {en}
}
@phdthesis{Li2015,
  author    = {Li, Han},
  title     = {Fabrication of Carbon Nanotube Thin Films by Evaporation-Induced Self-Assembly},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-123407},
  school      = {Universit{\"a}t W{\"u}rzburg},
  pages     = {159},
  year      = {2015},
  abstract  = {In summary, we have prepared single-wall carbon nanotube (SWNT) thin films by the method of evaporation-induced self-assembly (EISA). Using the scalable two-plate or lens setups, sorts of different film types or patterns of SWNTs has been successfully fabricated directly from the evaporation of solvents and could be precisely controlled by the concentrations of SWNT in ambient conditions. The special geometry of meniscus as the capillary bridge has not only given rise to a much higher efficiency of fabrication than what previously reported but also allowed us to monitor the pinning and depinning process carefully and further investigate the mechanism underlying the formation of different film morphologies. In contrast with the conventional "stick-slip" model, we have provided the new dynamical pinning and zipping model for the contact line (CL) behavior. By analyzing the motion of CL and varying deposited patterns, the traditionally so-called "stick" state should be treated as a dynamical pinning process due to the interfacial tension contrast between SWNT-covered and bare silicon surface. Besides, the plausible one-step "slip" motion could be dominated by the zipping-like kink propagation. In addition, the experiments with heated substrates at higher temperatures between 30°C and 50 °C have shown that the striped pattern could be fabricated by both much lower SWNT and SDS concentrations than that in room temperature, which is consistent with our model of interfacial tension contrast. In this situation, the deposition rate was increased but the quality of SWNT alignment was undermined because the corresponding moving velocity of SWNT was also too fast for SWNTs to rotate when the evaporative rate was high. The similar results were identified by the SWNT/polymer conjugates dispersed in chloroform under the similar setups and other identical conditions. The typical breathing motion of dynamical pinning and zipping-like propagation for depinning were confirmed by the new suspensions despite that some morphological parameters changed dramatically compared with that from the aqueous solution. For example, the spacing between stripes reached 100 µm ~ 200 µm because the large contact angle contrast between HDMS- and SWNT-covered surface accompanies with the high evaporation rate of chloroform in the pinning and depinning process. Likewise the average CL velocity for fabrication reached around 20 µm/s due to the much higher evaporation rate of chloroform than water. Using alike suspensions, the modified EISA method called dose-controlled floating evaporative self-assembly (DFES) was employed to implement the self-assembly of SWNTs on the water/air interface and then deposit them on solid substrate by directed floating. Although the stripes were fabricated successfully by drops with certain doses and SWNT concentrations, there inevitably existed randomly oriented SWNTs from the water surface that built networks between the stripes containing well-aligned tubes. In order to slow down the evaporation rate and monitor the process detailedly, we used chlorobenzene as the solvent instead of chloroform and find the typical pinning/depinning movement of the CL. A preliminary analysis of the results in terms of chlorobenzene implied that the CL possibly followed the similar pinning/depinning process in consistence with our model with capillary bridge. In the last part of the thesis, the primary research on the optical properties of these stripes of ultrahigh purity semiconducting nanotubes was conducted by fluorescence microscopy and photoluminescence excitation (PLE) spectroscopy. The energy transfer of the photogenerated excitons was confirmed between different tube species with controlled band gaps. In short, the experiments performed in this thesis allowed to gain new insights about the fabrication of large-area SWNT thin films by the cost-effective solution-processed method and most importantly to uncover its intrinsic mechanism as well. Combined with the separation and selection technique like density gradient centrifugation or polyfluorene derivatives assisted method, highly monodisperse semiconducting nanotubes could be deposited into organized, controllable and functional arrays. Beyond the ambient conditions, precise control for the evaporation under preset temperature and vapor pressure could possibly extend the technique to the industry level. Assisted by some other mature techniques such as roll-to-roll printing, the cost-effective method could be widely used in the manufacture of various thin film devices. More complex 2D or even 3D structures could be designed and accomplished by the method for the functional or stretchable requirements. Further research on the fundamental exciton transition and diffusion in different networks or structures of SWNTs will be the significant precondition for the real applications. Looking ahead, from the individual carbon nanotube to its thin film, this promising material with outstanding properties had many challenges to overcome before the real-world applications. Thanks to the availability of pure and well-defined materials, the scalable solution-processed approaches for fabrication of thin films should be able to unlock the potential of carbon nanotubes and exploit them in (opto-)electronic devices in the foreseeing future.},
  subject      = {Kohlenstoff-Nanor{\"o}hre},
  language  = {en}
}
@phdthesis{Rehm2015,
  author    = {Rehm, Stefanie},
  title     = {Spermine-functionalized Perylene Bisimide Dyes: Synthesis and Self-assembly in Water},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-123201},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2015},
  abstract  = {The main objective of this thesis was the design and synthesis of perylene bisimide dyes with sufficient water-solubility for the construction of self-assembled architectures in aqueous solutions. Beside these tasks another goal of this project was the control over the self-assembly process in terms of aggregate size and helicity, respectively. Within this thesis an appropriate synthesis for spermine-functionalized perylene bisimide dyes was developed and conducted successfully. The characterization of these building blocks and their course of self-assembly were investigated by NMR, UV/Vis and fluorescence spectroscopy as well as by atomic force and transmission electron microscopy. For the better understanding of the experimental results theoretical calculations were performed.},
  subject      = {Perylenderivate},
  language  = {en}
}