Advanced Materials

Cover image for Advanced Materials

1997

Volume 9, Issue 10

Pages fmi–fmi, 776–846

  1. Masthead

    1. Top of page
    2. Masthead
    3. Materials Forum
    4. Essay
    5. Review
    6. Communications
    7. Research News
    8. Book Reviews
    1. Masthead (page fmi)

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19970091001

  2. Materials Forum

    1. Top of page
    2. Masthead
    3. Materials Forum
    4. Essay
    5. Review
    6. Communications
    7. Research News
    8. Book Reviews
    1. Materials Forum (page 776)

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19970091002

  3. Essay

    1. Top of page
    2. Masthead
    3. Materials Forum
    4. Essay
    5. Review
    6. Communications
    7. Research News
    8. Book Reviews
    1. Materials science in Europe (pages 779–781)

      Prof. Franz Jeglitsch

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19970091003

      Topics of particular concern to materials scientists in Europe are briefly outlined by Professor Franz Jeglitsch, the President of the German Materials Society DGM. These include the fact that Europe invests significantly less of its gross national product in research than the USA of Japan, that Europe is less successful in converting scientific competence into new products or market share than its competitors, and recent trends in the number of students reading scientific and engineering disciplines. Ways of tackling these points, e.g., by public relations work, are suggested.

  4. Review

    1. Top of page
    2. Masthead
    3. Materials Forum
    4. Essay
    5. Review
    6. Communications
    7. Research News
    8. Book Reviews
    1. Surface chemistry of Luminescent Silicon Nanocrystallites (pages 783–793)

      Prof. Michael J. Sailor and Dr. Eric J. Lee

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19970091004

      The rational modification of porous and single-crystalline silico surfaces is of particular interest for technologies based on silicon. Porous silicon, such as the layer shown in the Figure, has many potential technological applications. In this review of chemical reactions developed for Si surface modification, both extensions of the chemistry of molecular Si compounds to surfaces and new surface chemistry are treated.

  5. Communications

    1. Top of page
    2. Masthead
    3. Materials Forum
    4. Essay
    5. Review
    6. Communications
    7. Research News
    8. Book Reviews
    1. Poly(3,4-ethylenedioxythiophene) (PEDOT) prepared via electrochemical polymerization of EDOT, 2,2′-Bis(3,4-ethylenedioxythiophene) (BiEDOT), and their TMS derivatives (pages 795–798)

      Dr. Gregory A. Sotzing, Prof. John R. Reynolds and Dr. Peter J. Steel

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19970091005

      The low potential, redox-active, highly stable conducting polymer PEDOT (poly(3,4-ethylenedioxythiophene)) has received much attention recently because of these properties, which are likely to lead to many applications. Here the synthesis of EDOT-TMS2 is reported (where TMS stands for trimethylsilyl and Bi indicates bis), together with the investigation of the electrochemical polymerization of these monomers using voltammetry and the electrochemical quartz crystal microbalance. The optical switching rates of the films on indium tin oxide are compared, showing that derivatization with TMS leads to improved characteristics.

    2. A glass-forming conjugated main-chain liquid crystal polymer for polarized electroluminescence applications (pages 798–802)

      Dr. Martin Grell, Prof. Donal D. C. Bradley, Dr. Mike Inbasekaran and Dr. E. P. Woo

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19970091006

      Electroluminescence and liquid crystallinity: these are the properties of a new spacerless conjugated main-chain liquid-crystalline (LC) polymer reported here. The thermal and spectroscopic properties of the new glass-forming poly-fluorene with octyl side chains (see Figure) are described, showing that polarized electroluminescent multilayer devices should be possible.

    3. White-light electroluminescence from self-assembled Q-CdSe/PPV multilayer structures (pages 802–805)

      Dr. Mingyuan Gao, Dr. Bernd Richter and Dr. Stefan Kirstein

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19970091007

      Inorganic nanoparticles in organic/inorganic hybrid devices are expected to have properties of interest for electroluminescence applications. The preparation of films of CdSe nanoparticles and poly(phenylenevinylene), PPV, by means of self-assembly is presented and photoluminescence and electroluminescence studies of these films are described. It is shown that nearly white-light emission is achieved from a twenty-layer film and that the emission orgininates most probably from the nanoparticles alone. The role of the PPV is discussed.

    4. Ultrathin cellulose ether network as a host matrix for alkylthiophene polymerization (pages 805–808)

      Dr. Christelle Denise Henry, Dr. Heiko Tebbe, Prof. Gerhard Wegner, Dr. Frank Arrnand and Dr. Annie Ruaudel-Teixier

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19970091008

      New insights into the mechanism of chain growth and phase formation in electropolymerization are expected from the work on ultrathin films described here. The Figure shows that the very rapid electrochemical polymerization of a thiophene derivative that occurs inside a multilayered assembly of a cellulose derivative on an electrode can be used as the basis of an imaging process.

    5. Molecular rectification in oriented polymer structures (pages 809–811)

      Dr. Carole Sentein, Dr. CéLine Fiorini, Dr. André Lorin and Dr. Jean-Michel Nunzi

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19970091009

      Oriented diode-like molecules in a polymer binder are the new approach described here for overcoming the problems associated with Schottky and p-n junctions in semiconductor devices. The principles relies on the intrinsic polar nature of the organic molecules used–which causes them to orient in an applied static electric field–and is expected to improve significantly the efficiency of polymeric semiconductor devices. The principle is outlined and experimental evidence presented for molecular rectification equivalent to ad distributed p-n homojunction.

    6. Mesoporous silica with micrometer-scale designs (pages 811–814)

      Hong Yang, Dr. Neil Coombs and Geoffrey A. Ozin

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19970091010

      A “three-way-templating” strategy is proposed for the growth of patterned, mesoporous silica on a gold-covered mica substrate. A model is suggested, as shown in the Figure, involving (from bottom to top) the co-assembly of alkanethiol-decorated gold surfaces, alkanethiol-surfactant hetero-bilayers, and surfactant-silicate assemblies.

    7. Multinuclear solid-state-NMR studies of hybrid organic-inorganic materials (pages 814–817)

      Markus Templin, Dr. Ulrich Wiesner and Prof. Hans W. Spiesss

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19970091011

      The powder of multinuclear solid-state NMR for the investigation of the structural aspects of hybrid organic-inorganic materials is demonstrated by the results presented here. It is shown that information about the organic groups can be obtained from 1H and 13C NMR and about the inorganic groups from 27Al and 29Si NMR; changes caused by the additional of a hardening component are revealed. Organic-inorganic materials are of interest because they combine properties typical of inorganic compounds with the favorable mechanical properties of synthetic polymers.

    8. Three-dimensional hexagonal close-packed superlattice of passivated Ag nanocrystals (pages 817–822)

      Steven A. Harfenist, Prof. Zhong L. Wang, Prof. Robert L. Whetten, Igor Vezmar and Dr. Marcos M. Alvarez

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19970091012

      Superlattices of self-assembled Ag nanocrystals have been prepared and the structure analyzed using a combination of techniques. It is shown that the supercrystals are hexagonally close-packed, attributed to a high proportion of icosahedral and decahedral particles. The Figure (a TEM image of the Ag supercrystals) illustrates that the crystals formed are predominantly triangular in morphology and can be as large as 3–5 μm.

    9. Induction of high-temperature superconductivity in pulsed laser ablated La2CuO4 thin films by room temperature chemical oxidation (pages 823–826)

      Simon T. Lees, Prof. Peter P. Edwards, Dr. Ian Gameson, Dr. Martin O. Jones, Marcin Slaski, Carmen Rial, Dr. Ulises Amador and Emilio Morán

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19970091013

      Facile fabrication of high-temperature superconducting La2CuO4 thin films through the combination of two seemingly disparate techniques is reported. Pulsed laser ablation is used to produce stoichiometric, c-axis oriented La2CuO4 thin films −3700 Å in thickness. The convenient method of controlled room-temperature chemical oxidation using aqueous sodium bromite is then utilized to introduce excess holes in the valance band of La2CuO4. This induces superconductivity in the otherwise antiferromagnetic semiconductor.

    10. Purification and size-selection of carbon nanotubes (pages 827–831)

      Dr. Jean-Marc Bonard, Dr. Thierry Stora, Dr. Jean-Paul Salvetat, Frédéric Maier, Dr. Thömas Stöckli, Dr. Claus Duschl, Dr. László Forró, Prof. Walt A. de Heer and Prof. André Châtelain

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19970091014

      A non-destructive method for purifying carbon nanotubes produced by are discharge is described. The nanotubes, in the form of a kinetically stable colloidal dispersion in a water–surfactant solution, are separated from the nanoparticles by filtration. The Figure shows that purified nanotubes after two filtration steps. Through controlled flocculation, nanotube size election is also possible.

  6. Research News

    1. Top of page
    2. Masthead
    3. Materials Forum
    4. Essay
    5. Review
    6. Communications
    7. Research News
    8. Book Reviews
    1. Growing large, well-oriented colloidal crystals (pages 833–835)

      Dr. Alfons van Blaaderen and Dr. Pierre Wiltzius

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19970091015

      The ability to manipulate colloidal crystallization is a challenging task, a consequence of teh size and Brownian motion of the colloid particles. As a direct result, temperature is not a suitable experimental parameter, even though it is important for tuning molecular crystal growth. Large single colloidal crystals with well-defined crystal orientations can, however, be grown through combined use of a polymer template and gravity. This and other methods that have been employed in an attempt to control colloid crystal growth, such as use of external fields, are described.

    2. Crystal engineering of molecular NLO materials (pages 837–842)

      Dr. Man Shing Wong, Dr. Christian Bosshard and Prof. Peter Günter

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19970091016

      Efficient second-order nonlinear optical materials are produced by optimizing the orientation of non-centro-symmetrically packed donor–acceptor chromophores. Practical approaches for inducing the favored alignment, for example incorporation of chirality into the chromophore (as shown in the Figure) and H-bond-induced self-assembly of ionic or molecular aggregates, are briefly reviewed.

  7. Book Reviews

    1. Top of page
    2. Masthead
    3. Materials Forum
    4. Essay
    5. Review
    6. Communications
    7. Research News
    8. Book Reviews

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