Project 5 – Functional Materials by Hierachical Self Assembly

Liposome-based nanocapsules
Ruysschaert, T. Germain, M. da Silva Gomes, J.F.P. Fournier, D. Sukhorukov, G.B. Meier, W. Winterhalter, M.
IEEE Transactions on NanoBioscience 3(1), 2004, 49-55
Here we present three different types of mechanically stable nanometer-sized hollow capsules. The common point of the currently developed systems in our laboratory is that they are liposome based. Biomolecules can be used to functionalize lipid vesicles to create a new type of intelligent material. For example, insertion of membrane channels into the capsule wall can modify the permeability. Covalent binding of antibodies allows targeting of the capsule to specific sites. Liposomes loaded with enzymes may provide an optimal environment for them with respect to the maximal turnover and may stab ...
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Soft nanotubes from amphiphilic ABA triblock macromonomers
Julie Grumelard , Andreas Taubert and Wolfgang Meier
Chem. Commun., 2004, (13), 1462 - 1463
Soft, water-filled polymer nanotubes of several tens of µm in length have been prepared via self-assembly of amphiphilic ABA-triblock macromonomers in aqueous media; the tubes are mechanically and chemically stable and can be loaded with water-soluble substances.
Polymer nanotubes that can be loaded with water-soluble substances may find applications in drug delivery and as highly specific templates for inorganic synthesis, suggest chemists at the University of Basel, in Switzerland, who prepared the materials.
“We developed a new, efficient, and easy method for the preparation of ch ...
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Plastikfolien mit biologischer Funktion
D. Streich, T. F. Haefele, W. P. Meier
Nachrichten aus der Chemie 2 (2004)
Blockcopolymere können zu membranartigen Überstrukturen aggregieren und dabei ultradünne Filme und nanometergroße Micellen bilden. Diese Polymerbausteine ermöglichen Funktionen, die mit konventionellen Lipiden nicht zu erreichen sind. Die Polymermembranen nehmen Kanalproteine auf, und solche Hybridsysteme können kontrolliert auf biologische Reize reagieren. ...
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Organometallic Block Copolymers as Catalyst Precursors for Templated Carbon Nanotube Growth
C. Hinderling, Y. Keles, T. Stöckli, H. F. Knapp, T. de los Arcos, P. Oelhafen, I. Korczagin, M. A. Hempenius, G. J. Vancso, R. Pugin, H. Heinzelmann
Advanced Materials, Volume 16, Issue 11 , Pages 876 - 879
no abstract ...
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Strong influence of buffer layer type on carbon nanotube characteristics
Teresa de los Arcos, M. Gunnar Garnier, Peter Oelhafen, Daniel Mathys, Jin Won Seo, Concepción Domingo, José Vicente García-Ramos and Santiago Sánchez-Cortés
Carbon, Volume 42, Issue 1, 2004, Pages 187-190
Carbon nanotubes (CNTs) have been grown by chemical vapor deposition in a vacuum chamber equipped with in situ photoelectron spectroscopy technique that allows for precise characterization of the chemical state of substrate and catalyst before the CNTs growth. The CNTs were grown onto Si wafers covered with thin buffer layers of Al, Al₂O₃, TiN, and TiO₂, using Fe as catalyst. Marked differences were observed both in growth rate and nanotube characteristics, as determined by SEM, TEM and micro-Raman spectroscopy, depending on the choice of buffer layer. ...
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The Influence of Catalyst Chemical State and Morphology on Carbon Nanotube Growth
Teresa de los Arcos, Michael Gunnar Garnier, Jin Won Seo, Peter Oelhafen, Verena Thommen, and Daniel Mathys
J. Phys. Chem. B; 2004; 108(23) pp 7728 - 7734
Carbon nanotubes grown by chemical vapor deposition have revealed differences in growth rate and characteristics depending on the underlying buffer layer. As determined by in situ photoelectron spectroscopy, iron catalyst deposited onto Si substrates covered with Al₂O₃, TiN, or TiO₂ underwent different chemical changes during annealing and exposure to C₂H₂ as function of buffer layer. Formation of thin tubes (2-4 walls) and fast growth rate were associated with conversion of Fe onto FeO particles on Al₂O₃ layers. On t ...
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Solid-Phase Synthesis of Oligo(triacetylene)s and Oligo(phenylenetriacetylene)s Employing Sonogashira and CadiotChodkiewicz-Type Cross-Coupling Reactions
Nils F. Utesch, François Diederich, Corinne Boudon , Jean-Paul Gisselbrecht, Maurice Gross
Helvetica Chimica Acta 87 (2004), 698 - 718
We describe the first polymer-supported synthesis of poly(triacetylene)-derived monodisperse oligomers, utilizing Pd0-catalyzed Sonogashira and CadiotChodkiewicz-type cross-couplings as the key steps in the construction of the acetylenic scaffolds. For our investigations, Merrifield resin functionalized with a 1-(4-iodoaryl)triazene linker was chosen as the polymeric support (R2; Figure and Scheme 3). The linker selection was made based on the results of several model studies in the liquid phase (Schemes 1 and 2). For the solid-support synthesis of the oligo(phenylene triacetylene)s 7b-7d, a s ...
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NMR Investigations into the Vase-Kite Conformational Switching of Resorcin[4]arene Cavitands
Vladimir A. Azov, Bernhard Jaun, François Diederich
Helvetica Chimica Acta, Volume 87, Issue 2 , Pages 449 - 462
We report the detailed investigation of temperature- and pH-triggered conformational switching of resorcin[4]arene cavitands 1-10 (Figs. 1, 8, and 9). Depending on the experimental conditions, these macrocycles adopt a vase conformation, featuring a deep cavity for potential guest inclusion, or two kite conformations (kite 1 and kite 2) with flat, extended surfaces (Schemes 1 and 2). The thermodynamic and kinetic parameters for the interconversion between these structures were determined by variable-temperature NMR (VT-NMR) spectroscopy (Figs. 2-7 and 10, and Tables 1 and 2). It was discovered ...
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Piezoelectric Response and Polarization Switching in Small Anisotropic Perovskite Particles
Ganesh Suyal, Enrico Colla, Roman Gysel, Marco Cantoni, and Nava Setter
Nano Letters, 4 (7), 1339 -1342, 2004
A hydrothermal processing route was used to produce anisotropic submicrometer particles of potassium niobate-tantalates and pure potassium niobate. Piezoelectric activity, switching polarization, and piezoelectric hysteresis loops were observed in these ferroelectric perovskite nanorods by means of AFM assisted detection of induced piezoelectric vibrations. Both lattice and domain wall contributions to the piezoelectric response were evidenced. ...
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