Advanced Materials

Cover image for Advanced Materials

June 1993

Volume 5, Issue 6

Pages 415–488

  1. Masthead

    1. Top of page
    2. Masthead
    3. Essay
    4. Reviews
    5. Communications
    6. Materials Forum
    7. Research News
    8. Book Reviews
    1. Masthead (page 415)

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050601

  2. Essay

    1. Top of page
    2. Masthead
    3. Essay
    4. Reviews
    5. Communications
    6. Materials Forum
    7. Research News
    8. Book Reviews
    1. Materials R & D in the electrical and electronics industry (pages 416–421)

      Prof. Claus Weyrich

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050602

      The training of R & D managers is just one of the many topics discussed by one of the senior figures in the research and development activities of Siemens. The planning of future R & D aims in the electronics industry, based on indentifying market requirements and producing materials faster than competitors which perform to the desired level at the desired price, and the various factors which affect this planning are discussed.

  3. Reviews

    1. Top of page
    2. Masthead
    3. Essay
    4. Reviews
    5. Communications
    6. Materials Forum
    7. Research News
    8. Book Reviews
    1. Hybrid Nanocomposite Materials—between inorganic glasses and organic polymers (pages 422–433)

      Prof. Bruce M. Novak

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050603

      The sol–gel process offers mild methods for the production of composite materials with domain sizes approaching the molecular level. Product organic–inorganic composites can be transparent and other properties range from those of elastomeric rubbers to high modulus materials. A polymerizable alkoxide used in the production of non-shrinking composite formulations is shown in the figure.

    2. Sol-gel processing of transition-metal alkoxides for electronics (pages 434–442)

      Dr. G. Rob Lee and Dr. Joe A. Crayston

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050604

      High-temperature superconductors, ferroelectric materials, electrochromic films, and semiconductors are just some of the materials which can be produced from transition-metal alkoxides using the sol–gel method. The method itself is outlined, the control of the various parameters, such as choice of precursor and medium, and stabilizing ligands, is discussed, and applications over a broad area of materials science are presented.

  4. Communications

    1. Top of page
    2. Masthead
    3. Essay
    4. Reviews
    5. Communications
    6. Materials Forum
    7. Research News
    8. Book Reviews
    1. AlH3(NMe3)2—a useful precursor to AlN (pages 443–445)

      Dr. Wilfried Rockensüß and Prof. Herbert W. Roesky

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050605

      The high-performance ceramic aluminum nitride has a high resistance to heat and aggressive media. These properties depend to a large degree on the purity of the material. As a result much effort has been invested in the search for new precursors to AlN for use in methods such as metal-organic chemical vapor deposition (MOCVD). The figure shows pure AlN powder produced from the title compound in an ammonia atmosphere.

    2. Prediction of the stoichiometry of cation radical salts of organic metals by thin layer cyclic voltammetry (pages 445–447)

      Dr. Roger Carlier, Dr. Pierre Frère, Dr. Marc Sallé, Dr. Jean Roncali, Prof. Michel Jubault, Prof. André Tallec and Prof. Alain Gorgues

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050606

      The detection of mixed valences in organic metals using thin layer cyclic voltammetry is reported. Although mixed valence is recognized as a prerequisite for superconductivity in cation radical salts this is the first report of a method which enables the reliable prediction of the conditions necessary for the production of a suitable cation radical stoichiometry. The method and its application to TTF derivatives are described.

    3. Ferromagnetically coupled decamethylmetallocenium salts of 2, 5-dimethyl-N,N′-dicyanoquinonediimine, [M(C5Me5)2][Me2DCNQI]⊙⊖, (M = Fe, Mn) (pages 448–450)

      Dr. Joel S. Miller, Carlos Vazquez, R. Scott McLean, Prof. William M. Reiff, Dr. Alexander Aumüller and Prof. Siegfried Hünig

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050607

      Cooperative magnetic interactions in organic materials (such as ferri- or ferromagnetic behavior) have been observed in only a few cases. The title compound, shown in the Figure, has been synthesized and represents a further step in the study of structure–function relationships in these materials, from which it is hoped the structures of higher performance materials can be predicted.

    4. Optical, electrochemical and photoelectrochemical properties of polyazulenes with substituents at C-2. Photoelectrochemical switching by light-pulse treatment (pages 450–453)

      Albert Mirlach, Michaela Feuerer and Prof. Jörg Daub

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050608

      Conducting, ferromagnetic, and electrochromic behavior is exhibited by polyazulene materials. Here, the synthesis and properties of a range of polyazulenes substituted at C-2 in the five membered ring are presented (the C-1 and C-3 positions are involved in the polymerization). The non-alternant azulenes are known to have a low ionization energy, a high electron affinity, and a narrow bandgap. The effect of the substituents on these properties is examined.

    5. Morphological and molecular processes observed using scanning tunneling microscopy on organic conductors (pages 453–458)

      Dr. Sergei N. Magonov, Dr. Georg Bar, Arkadij Y. Gorenberg, Prof. Eduard B. Yagubskii and Prof. Hans-Joachim Cantow

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050609

      Step-by-step surface layer restoration in organic superconducting salts has been observed using STM. The Figure shows a step, approximately 1.8 nm in height, with an uneven boundary. Over a period of time the step edge is seen to “heal” under positive tip bias, where the current flows from the tip to the sample. Under reversed bias the degradation of the surface has been observed.

    6. EPR and optical absorption spectra of reduced buckminsterfullerene (pages 458–461)

      Dr. Martin Baumgarten, Andreas Gügel and Lileta Gherghel

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050610

      The unambiguous identification of the various redox states of C60 is of importance in many areas of fullerene research, such as charge transfer studies between conducting polymers and C60, or the study of the distribution of charged states in solid-state-doped samples. This combined ESR and optical absorption spectroscopic study represents the most complete analysis of the anionic states of buckminsterfullerene, from the monoanion to the hexaanion, so far reported.

    7. X-ray determination of the crystal structure and orientation of vacuum evaporated sexithiophene films (pages 461–464)

      Dr. Bernard Servet, Dr. Simone Ries, Dr. Marie Trotel, Dr. Patrick Alnot, Dr. Gilles Horowitz and Dr. Francis Garnier

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050611

      The crystalline orientation of oligothiophenes has a profound effect on the electronic properties of the materials, which are of interest for example in the construction of all-organic field-effect transistors. Here, an X-ray diffraction study of oligothiophene films is reported and the possible routes to improving the crystalline orientation discussed. It is found that α-substitution or indeed heating of the substrate can lead to increased orientation of the oligomers.

  5. Materials Forum

    1. Top of page
    2. Masthead
    3. Essay
    4. Reviews
    5. Communications
    6. Materials Forum
    7. Research News
    8. Book Reviews
    1. Materials Forum (pages 464–465)

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050612

  6. Research News

    1. Top of page
    2. Masthead
    3. Essay
    4. Reviews
    5. Communications
    6. Materials Forum
    7. Research News
    8. Book Reviews
    1. Dendrimeric silanes (pages 466–468)

      Dr. Alexander W. van der Made, Dr. Piet W. N. M. van Leeuwen, Janine C. de Wilde and Raymond A. C. Brandes

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050613

      Silane dendrimers have potential for applications such as stable micelles, building blocks for nanotechnology, X-ray beam scattering and cores for star-branched polymers. The Figure shows a first generation silane dendrimer in which the unsaturated terminal groups (the starting points for the production of the second generation) can be seen. The synthesis and properties of these species are discussed.

    2. Strengthening glasses and ceramics: Composite technology (pages 468–473)

      Graham Partridge

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050614

      Composite technology offers the opportunity to provide a large number of interfaces in a material which deflect crack fronts and dissipate the energy of fracture. Part II of this discussion examines the various types of composites, for example particle or whisker reinforcement, and analyzes their performance profiles with a special emphasis on the strengthening of glasses and glass-ceramics.

    3. Scanning tunneling microscopy of nanoscale electrodeposited superlattices (pages 474–476)

      Prof. Jay A. Switzer and Dr. Teresa D. Golden

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050615

      Artificially layered superconductor materials based on crystalline multilayer structure are of potential interest due to the unusual quantum effects which could be expected in materials of this type. Scanning tunneling microscopy has recently been used (e.g. see Figure) to measure the modulation wavelength (the bilayer thickness) and to estimate the composition profile in such superlattices.

    4. Polymeric materials with arylenevinylene segments—synthesis and architecture (pages 477–479)

      Dr. Andreas Greiner

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050616

      Poly-p-phenylenevinylene is of interest due to its electrical and optical properties. It is electrically conductive upon doping, it is photoconductive, NLO active, and exhibits electrically induced luminescence. Recent progress made in the synthesis of pure and well-defined materials of this type are reviewed and the various strategies for the design of materials yielding the required properties discussed.

    5. 3-D optical data storage by two-photon excitation (pages 479–481)

      Prof. James H. Strickler and Prof. Watt W. Webb

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050617

      Increased data density and media capacity is a constant goal of research into optical storage. These-dimensional optical storage offers this large increase because the volume density limit is 1/λ3 rather than the 1/λ2 achievable with 2-D storage. Holographic storage and spectral hole burning have been examined in the past; here an alternative is presented based on two-photon excitation.

  7. Book Reviews

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

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