Advanced Materials

Cover image for Advanced Materials

September 1993

Volume 5, Issue 9

Pages 603–688

  1. Masthead

    1. Top of page
    2. Masthead
    3. Essay
    4. Reviews
    5. Communications
    6. Research News
    7. Materials Forum
    8. Book Reviews
    1. Masthead (page 603)

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050901

  2. Essay

    1. Top of page
    2. Masthead
    3. Essay
    4. Reviews
    5. Communications
    6. Research News
    7. Materials Forum
    8. Book Reviews
    1. The amoeba—a flexible organism called RIKEN (pages 604–607)

      Prof. Wolfgang Knoll

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050902

      Two aims of RIKEN, the Japanese Institute of Physical and Chemical Research, are “to conduct comprehensive research in science and technology” and “to disseminate the results of research and new technological developments”. How RIKEN is organized and managed in order to pursue these goals is the subject of this essay, which likens RIKEN to a unicellular, multinuclear animal living in the Sea of Japan. Details are given of the Frontier Research Program, which is designed to further cooperation with the wider international research community.

  3. Reviews

    1. Top of page
    2. Masthead
    3. Essay
    4. Reviews
    5. Communications
    6. Research News
    7. Materials Forum
    8. Book Reviews
    1. Microemulsions and organogels: Properties and novel applications (pages 608–619)

      Dr. Gareth D. Rees and Prof. Brian H. Robinson

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050903

      The phase behavior of surfactant – oil – water mixtures gives rise to a wide variety of possible equilibrium systems, including microemulsions. The Figure shows one model for a gelatin-containing microemulsion-based organogel deduced from data from small-angle neutron scattering. The conditions required and the stability of microemulsions are briefly reviewed before their applications, and the supramolecular architectures they provide, are considered in more detail.

    2. Structural studies on Superconducting materials and fullerites by electron microscopy (pages 620–629)

      Prof. Gustaaf van Tendeloo and Prof. Severin Amelinckx

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050904

      High-resolution electron microscopy (HREM) has proved invaluable in the study of local structure—i.e. defects—which in many cases govern the physical, chemical, and electrical properties of materials. The use of HREM in investigations of cuprate high-temperature superconductors is reviewed, especially for compounds in which substituents replace some of the copper. HREM can also be very successfully combined with other techniques, such as electron diffraction, as is demonstrated by results of research on the structure and phase transitions of C60 and C70.

  4. Communications

    1. Top of page
    2. Masthead
    3. Essay
    4. Reviews
    5. Communications
    6. Research News
    7. Materials Forum
    8. Book Reviews
    1. Electrochemical muscles: Micromachining fingers and corkscrews (pages 630–632)

      Dr. Elisabeth Smela, Dr. Olle Inganäs, Dr. Qibing Pei and Ingemar Lundström

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050905

      Millimeter-scale polymer “fingers” are reported, in which the volume changes of the conjugated polymer polypyrrole that occur in response to electrochemical reduction or oxidation are used to create electrically controlled mechanical actuators. The short bilayer gold and polypyrrole fingers in the Figure can be made to curl by reducing the polypyrrole. The primitive fabrication technique used to make these fingers points the way to the microminiaturization of these artificial muscles.

    2. New chromophores containing sulfonamide, sulfonate, or sulfoximide groups for second harmonic generation (pages 632–634)

      Jody E. Beecher, Prof. Tony Durst, Prof. Jean M. J. Fréchet, Dr. Adelheid Godt, Amy Pangborn, Dr. Douglas R. Robello, Dr. Craig S. Willand and Dr. David J. Williams

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050906

      Efficient blue light generation by SHG for use in optical storage etc. requires materials that display not only a large nonlinear response and but also optical transparency at the wavelengths of both the laser and the blue light. New chromophores containing sulfonamide, sulfonate, or sulfoximide groups are described that come nearer to this ideal. The optical transparency of electron-donor and electron-acceptor substituted conjugated π systems studied previously, which was found to be poor owing to a low-lying charge-transfer absorption, is shown to improve when the acceptor group is sulfonamide or sulfonate ester.

    3. Nanometer-sized colloidal germanium particles: Wet-chemical synthesis, laser-induced crystallization and particle growth (pages 634–636)

      Andreas Kornowski, Dr. Michael Giersig, Dr. Ralf Vogel, Dr. Abdelkarim Chemseddine and Dr. Horst Weller

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050907

      Nanometer-sized semiconductor particles are currently being intensively investigated in many fields of physics and chemistry—especially since the discovery of visible luminescence in porous silicon. This is one of the first papers to concentrate on the synthesis of IV – IV nanoparticles. A purely wet-chemical room-temperature synthesis is described that leads to stable nanometer colloidal germanium particles after laser illumination. The size of the crystallites can be controlled by adjusting the illumination conditions. The preparation technique detailed here is not restricted to germanium but can also be applied to other IV–IV semiconductor particles.

    4. Synthesis and electropolymerization of 3-(3,3,4,4,5,5,6,6,6-nonafluorohexyl-1-dimethylsilyl thiophene): Reduction of steric hindrance in 3-substituted poly(thiophenes) by fluorophilic interactions (pages 637–639)

      DR. Christine Thobie-Gautier, Prof. Alain Guy, Prof. Alain Gorgues, Prof. Michel Jubault and DR. Jean Roncali

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050908

      Fluoropolymers and conjugated poly(thiophenes) both exhibit exceptional properties: the fluoropolymers are known for their low coefficient of friction, high thermal and chemical stability, hydrophobicity and lipophobicity, while poly(thiophenes) allow the design of tailored conducting polymers. A combination of these properties would be of great interest. The title compound (see Figure) can be readily electropolymerized, yielding a hydrophobic conjugated polymer with doping level and conductivity comparable to those of its alkyl-substituted analogue.

    5. Modeling the elementary steps of low-pressure diamond deposition (pages 639–643)

      Prof. Jürgen Biener, Uwe. A. Schubert, Angelika Schenk, Dr. Bernd Winter, Dr. Carsten Lutterloh and Prof. Jürgen Küppers

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050909

      Low-pressure diamond deposition from hydrocarbon/hydrogen gas-phase mixtures was discovered over 20 years ago, but the exact deposition mechanism remained unknown. Work reported here confirms preferential graphite erosion to be the rate-controlling step, as had been assumed by some researchers earlier, and identifies reaction pathways by which the graphitic constituents of the deposit are preferentially removed. Model systems of C:H a few monolayers thick were used to show that dehydrogenation, erosion, and hydrogenation all play a part.

    6. Well-aligned carbon nanotubules (pages 643–646)

      Jyun-Hwei Hwang, Wen-Kuan Hsu and Prof. Chung- Yuan Mou

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050910

      The alignment of carbon nanotubules greatly influences their transport properties, for example their electrical conductivity. Since these properties are important for potential applications in electronic devices, it is desirable to be able to control nanotube morphology during synthesis. An arc production method is presented that uses copper-mixed graphite as the positive electrode, resulting in the degree of alignment shown in the Figure.

    7. A new conducting charge transfer complex from a model thiophene oligomer and a Keggin-type heteropolyanion (pages 646–650)

      Bruno Fabre and Prof. Gérard Bidan

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050911

      A conducting charge transfer complex between a sexithienyl radical cation and a Keggin-type heteropolyanion (PMo12Omath image) has been synthesized and characterized. These large inorganic ions confer new properties on polymers to which they are linked, for example, multiple redox exchanges, paramagnetism, electrochromism, and catalytic action. The thiophene hexamer is the best compromise between a long-conjugated system and a processable material, and can be considered a typical poly(thiophene) model, thus allowing a better understanding of the electronic interactions between the conducting polymer poly(3-methylthiophene) and the dopant anion PMo12Omath image.

    8. A solid-state electrochromic device based on polyaniline, prussian blue and an elastomeric electrolyte (pages 650–652)

      DR. Eliana A. R. Duek, Prof. Marco-A. De Paoli and DR. Marina Mastragostino

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050912

      Advantages of solid-state electrochemical devices are the ease of production, no possibility of leakage, and no electrolyte evaporation. One result of the search for such a device is the electrochromic display sketched in the Figure, which uses polyaniline and Prussian Blue as the active electrochromic materials and an elastomer containing Li-ClO4 as the solid-state electrolyte.

    9. Methylzinc or methylcadmium-N,N,N-trimethyl- propylenediaminedithiocarbamates: Precursors for zinc or cadmium sulfide. The X-ray crystal structure of methylcadmiumtrimethylpropylene- diaminedithiocarbamate benzene solvate (pages 653–654)

      DR. M. Azad Malik, Majid Motevalli, Tahir Saeed and DR. Paul O'Brien

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050913

      Deposition of metal chalcogenides by metal-organic chemical vapor deposition can be achieved using various systems, including alkyl-metal-dithio- or diselenocarbamates. Initial attempts to modify the behavior of such precursors by changing the nature of the carbamato ligand are reported. Among the results presented are the synthesis and characterization of the two title compounds and the single-crystal X-ray structure of one of them. For both the zinc and cadmium derivatives the films grown were of a better quality than those grown from the parent compounds or from zinc- or cadmium-diethyldithiocarbamate.

  5. Research News

    1. Top of page
    2. Masthead
    3. Essay
    4. Reviews
    5. Communications
    6. Research News
    7. Materials Forum
    8. Book Reviews
    1. Engineering oxide–oxide and metal–oxide microstructures in directionally solidified eutectics (pages 657–662)

      Prof. Alexandre Revcolevschi and DR. Guy Dhalenne

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050914

      Very regularly aligned composite structures made of the two phases of a eutectic can be fabricated by unidirectional solidification of eutectics from the melt. A recent innovation is the use of chemical reactions taking place at the eutectic interface to produce new aligned composite materials. An example of this can be seen in the Figure, an SEM micrograph of an Ni/NiO interface showing long forks of Ni in an oriented NiO–ZrO2(CaO) eutectic.

    2. Charge transport in random organic photoconductors (pages 662–665)

      Prof. Heinz Bässler

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050915

      Electrophotography, the technology of modern photocopiers, is the only area in which the photoelectronic properties of organic materials are exploited on a large-scale industrial basis. Neither crystalline nor polycrystalline materials can meet the requirements set by current designs, and polymers are obvious candidates. However, these need to be improved by controlling (or eliminating) the charge-carrier trapping and by understanding how their morphology and disorder affect charge transport. Recent work on the photoconductivity of organic solids is described, indicating that although progress has been made much remains to be done.

    3. Nematic liquid crystalline mineral polymers (pages 665–668)

      DR. Patrick Davidson, Jean-Christophe Gabriel, DR. Anne-Marie Levelut and DR. Patrick Batail

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050916

      Anisotropic fluids are demonstrating that liquid crystals need not be organic. Recent theories predict the existence of lyotropic liquid crystalline phases for particular anisotropies and concentrations of the fluid-constituting objects, regardless of their chemical nature. Attention has been focused on the solution-phase chemistry of LiMo3Se3, which dissolves in highly polar solvents to give very long Mo3Se3 strings (the Figure shows a texture photograph of LiMo3Se3 in N-methylformamide).

    4. The multiple tunnel junction and its application to single-electron memories (pages 668–671)

      DR. Kazuo Nakazato and Prof. Haroon Ahmed

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050917

      Single-electron memories and single-electron logic circuits are two devices that can be constructed from multiple tunnel junctions (MTJs). The electrical characteristics of this basic building block are described, and the fabrication of very small MTJ devices is outlined. The simple structure of the MTJ and the low power consumption and small size of MTJ devices could open up a new era in electron device technology, with devices being constructed from materials completely different from those used in the present semiconductor industry.

    5. Conducting polymers—materials of commerce (pages 671–676)

      Dr. Joel S. Miller

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050918

      Conducting-polymer-based poducts that are commercially available are the topic of this second part of a two-part article (the first half appeared last month). Many people are not aware that conducting polymers have reached the marketplace in the form of “coin”-shaped batteries (see Figure). 3.5.″ floppy disks, and electrostatic loudspeakers, as well as being available for commercial processes and as raw materials.

  6. Materials Forum

    1. Top of page
    2. Masthead
    3. Essay
    4. Reviews
    5. Communications
    6. Research News
    7. Materials Forum
    8. Book Reviews
    1. Materials forum (pages 678–680)

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050919

  7. Book Reviews

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

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