Advanced Materials

Cover image for Advanced Materials

February 1994

Volume 6, Issue 2

Pages fmi–fmi, 101–178

  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 fmi)

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19940060201

  2. Essay

    1. Top of page
    2. Masthead
    3. Essay
    4. Reviews
    5. Communications
    6. Research News
    7. Materials Forum
    8. Book Reviews
    1. Copernicus (pages 101–105)

      Dr. Ingo Hussla and Natasha Us

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19940060202

      COPERNICUS is a European Community program supporting cooperation in science and technology with Central and Eastern European countries and the Newly Independent States of the former Soviet Union. The conditions of the call for proposals that has just been issued by the Commission of the European Communities are explained, and the opportunities offered by “joint research projects” and “concerted actions/networks” outlined. The COPERNICUS research sectors and priority themes that are especially relevant to advanced materials are introduced in more detail.

  3. Reviews

    1. Top of page
    2. Masthead
    3. Essay
    4. Reviews
    5. Communications
    6. Research News
    7. Materials Forum
    8. Book Reviews
    1. Inorganic—Organic Polymers (pages 106–115)

      Prof. Harry R. Allcock

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19940060203

      Polymers with an inorganic backbone and organic or organometallic side groups are one of the most promising approaches to new materials that combine the advantages of organic polymers with those of inorganic solids. Properties conferred by particular backbone elements and side groups are discussed, and methods of synthesis briefly outlined. The figure shows the result of a novel variation of ring-opening polymerization.

    2. Fascinating phenomena in Surfactant Chemistry (pages 116–129)

      Prof. Heinz Hoffmann

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19940060204

      Spontaneous self-assembly of simple surfactant molecules in water leads to a multitude of micellear structures such as globules, rods, disks, and vesicles. This macroscopic ordering leads to remarkable macroscopic properties, for example, a yield stress, complex fluid behavior, or iridescence under illumination. The various phases of surfactants are explored and the phenomenon of iridescence examined more closely. The network character of surfactant soultions is considered, the behavior of namatic and cholesteric phases in magnetic fields is described, and, finally, some shear-induced phenomena are sketched.

  4. Communications

    1. Top of page
    2. Masthead
    3. Essay
    4. Reviews
    5. Communications
    6. Research News
    7. Materials Forum
    8. Book Reviews
    1. Arg—Gly—Asp peptides in polyurethanes: Design, synthesis, and characterization (pages 130–132)

      Dr. Siew Peng Ho and Dustin H. O. Britton

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19940060205

      Peptide-containing polymers have been synthesized with the aim of using polymers as synthetic scaffolds for biologically active peptide sequences. Introducing the peptide shown in the figure during polyurethane synthesis resulted in a series of peptide-polymer hybrids containing the Arg-Gly-Asp sequence, which plays a central role in cel adhesion.

    2. Tuning of photo- and electroluminescence in alkylated polythiophenes with well-defined regioregularity (pages 132–135)

      Richard E. Gill, George G. Malliaras, Jurjen Wildeman and Prof. Georges Hadziioannou

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19940060206

      Color tuning of luminescence via molecular engineering of the active polymer is important for the commercial application of π-conjugated polymers in photonic devices. The synthesis of a series of regiospecific alkylated polythiophenes is described, in which the effective conjugation length could be varied by altering the length of the coplanar blocks between head-to-head dyads. It is demonstrated that the color-tuned materials obtained by this novel approach are potentially suitable for applicationin displays and other devices.

    3. Oligothiophenes as models for polythiophenes. The crystal and molecular structures of 3″, 4″-dibutylpentathiophene and 3′,3″ ″,4′, 4″ ″-tetrabutylhexathiophene (pages 135–138)

      Dr. Ju-Hsiou Liao, Dr. Michael Benz, Dr. Eugene Legoff and Prof. Mercouri G. Kanatzidis

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19940060207

      Knowledge of the crystal structures of oligothiophenes is necessary if progress is to be made towards understanding the structure-property relationships of polythiophenes, since single crystals of these conducting polymers are not available. Two oligothiophene derivatives (one of which is shown in the Figure) have been designed, synthesized, and struturally characterized.

    4. Electropolymerization of thiophene derivatized with a mesogenic substituent (pages 138–142)

      Dr. Christine Thobie-Gautier, Prof. Yuves Bouligand, Prof. Alain Gorgues, Prof. Michel Jubault and Dr. Jean Roncali

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19940060208

      The synthesis of a new mesogenic thiophene derivative is reported. The monomer, which exhibits interesting mesophase properties, contains a p-cyanobiphenyl group that is electronically and sterically decoupled from the thiophene ring by means of an octyl spacer. Electropolymerization of this monomer produces a polymer with conjgation lenght, conductivity, and electroactivity comparable to those of poly (3-alkylthiophenes). The use of indirect substitutional effects to control the long-range order and dimensionality of conducting polymers is discussed.

    5. Surface investigations of silylated substrates by TOF-SIMS (pages 142–144)

      Dr. Birgit Hagenhoff, Prof. Alfred Benninghoven, Dr. Karl Stoppek-Langner and Dr. Joseph Grobe

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19940060209

      Organosilicon compounds have found widespread use as protective coatings, especially agaist corrosive surface phenomena. TOF-SIMS data are presented here that help to elucidate the products formed when organosilicon agents are coupled to oxidic surfaces. Evidence is found for silsequioxanes and their homo-derivatives (see Figure), whose shynthesis normally requires special preparative conditions.

    6. Weak ternary CT salts formed by α-keggin polyanions and tetraphenylporphyrinato ZnII in the presence of halide ions (pages 145–147)

      Dr. Donato Attanasio and Dr. Fiorella Bachechi

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19940060210

      Molecular complexes between α-Keggin polyanions and tetraphenylporphyrinato ZnII that are uexpectedly stable have been obtained in the presence of an ancillary donor anion such as a halide. X-ray structure determination reveals intgrated organic-inorganic stacks with alkyl ammonium cations acting as spacers. Development of these compounds, which combine thermally and photochemically redox active units, may lead to molecular materials with interesting electro-and photochromic properties.

    7. Germanium nanoclusters: Chemical vapor deposition of digermane in zeolite Y and mordenite (pages 147–150)

      Dr. ÖMer Dag, Prof. Alex Kuperman and Dr. Geoffrey A. Ozin

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19940060211

      Uniform arrays of intrazeolite germanium nanoclusters have been produced by the topotactic chemical vapor deposition of digermane within the diamond network of α-cages of acid zeolite Y and the main channel of mordenite. The conditions within the zeolite hosts enusure that the Ge2H6 CVD-type anchored precursors self-assemble to produce the anchored (Ge8)n nanoclusters shown in the Figure.

    8. Dielectric relaxation in a new cyclic liquid-crystalline oligosiloxane (pages 150–152)

      Eckhard Jakob, Dr. Franz-Heinrich Kreuzer, Dr. Norman Häberle and Prof. Wolfgang Haase

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19940060212

      Polysiloxanes with mesogenic side chains are suitable model compounds dor the study of molecular dynamics. The first dielectric relaxation data are presented here for a cyclic oligosiloxane having a degree of oligomerization of 5, a cyanophenylbenzoate group as the terminal dipole, and a spacer length of 3. The phase sequence was determined by means of X-ray diffraction, differential scanning calorimetry, and polarizing microscopy. Reasons for the strong dependence of physical properties on the degree of oligomerization are discussed.

    9. New nanocomposites based on “tailor dressed” magnetic particles in a polypyrrole matrix (pages 152–155)

      Dr. Gérard Bidan, Dr. Olivier Jarjayes, Dr. Jean Marc Fruchart and Dr. Etienne Hannecart

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19940060213

      Nanometer-sized magnetic particles can be included into polypyrrole to produce composites by means of a novel method involving ferrofluids, in which a magnetic core such as γ-Fe2O3 is surrounded by an anionic complexing shell (see Figure). This organic coating, leading to the formation of a macroanion, allows the ion to act as a classical doping ion during the polymerization.

  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. Conjugated polymers exhibiting liquid crystallinity (pages 156–159)

      Prof. Luping Yu and Zhenan Bao

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19940060214

      Various solubel and fusible liquid crystalline conjugated polymers can be synthesized due to recent progress in the use of the Stille coupling reaction and the Heck reaction. Evidence of nematic liquid-crystalline phases in these polymers–arising from the rigid-rod nature of the conjugated polymer backbone—is provided, and it is demonstrated that properties such as Tm, Tc, the solubility and the fusibility can becontrolled by changing the side groups.

    2. Stacked organometallic arrays (pages 159–162)

      Prof. Myron Rosenblum

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19940060215

      Stacks of planar organic or organometallic units can be either a result of self-assembly that takes place upon crystallization or a consequence of primary molecular structure. Common features in the latter case are divalent and bifacially coordinated ring bridging elements and also two-center briding elements (Figure). The challenge of these materials is reviewed and attention is drawn to their potential as superconductors and molecular-based ferromagnets.

    3. Gas sensing properties of phthalocyanine langmuir—blodgett films (pages 162–164)

      Dr. Sabarna Mukhopadhyay and Dr. Cyril A. Hogarth

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19940060216

      Ideal microsensors would be cost effetive, efficient, and stable, detect low concentrations of a certain gas in a working enviornment, and be able to operate in real time, i.e., monitor continuously. Among the compounds being ivestigated for development into microsensors are the phthalocyanines (Pcs), in particular in the form of thin films. The advantages and problems of Pc thin films are discussed, and the latest results for the detection of toluene and nitrogen oxides in air, including the response and recovery times, are presented.

    4. The safety of ceramic balls on metal stems in hip arthroplasty (pages 165–170)

      Prof. Günther Heimke

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19940060217

      The safety of hip replacement systems is influenced by, for example, the materials of the ball and stem or taper, the method of joining, heir shape, and the state of their surfaces. These factors, and specifiations for manufacturers and in the operating theater, are briefly reviewed. The metal taper shown in the Figure has a typical defect —it does not meet the straightness requirement—which could lead to failure.

  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 171–172)

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19940060218

  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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