Advanced Materials

Cover image for Advanced Materials

January 1993

Volume 5, Issue 1

Pages 7–67

  1. Masthead

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

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050101

  2. Essay

    1. Top of page
    2. Masthead
    3. Essay
    4. Reviews
    5. Communications
    6. Research News
    7. Talking Point
    8. Book Reviews
    1. The European Physical Society (pages 8–10)

      Prof. Maurice Jacob

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050102

      The President of the European Physical Society describes the structure and activities of the EPS in relation to the national societies and the European Commission. One point of particular activity is the development of east–west research collaborations, through arranging exchange visits, and providing equipment and funds. Other topics covered are the EPS conferences and publication programs.

  3. Reviews

    1. Top of page
    2. Masthead
    3. Essay
    4. Reviews
    5. Communications
    6. Research News
    7. Talking Point
    8. Book Reviews
    1. Polyrotaxanes: Molecular composites derived by physical linkage of cyclic and linear species (pages 11–21)

      Prof. Harry W. Gibson and Prof. Hervé Marand

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050103

      Molecular composites consisting of cyclic molecules whose cavities have been pierced by linear molecules (see Figure) were discussed as early as 1910. However, recently interest in these molecules, which are known as rotaxanes, and their polymeric derivatives has intensified due to their unique property profiles which cannot be compared with those their components. Progress with rotaxanes and related compounds such as catenanes is reviewed.

    2. Direct synthesis of semiconductor quantum-wire and quantum-dot structures (pages 22–29)

      Richard Nötzel and Prof. Klaus H. Ploog

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050104

      The quantum confinement of electrons and holes in low-dimensional semiconductor structures strongly influences the properties of “quantum wires and dots” and therefore has an important impact on the performance of high-speed electron and optoelectronic devices. The fabrication of such structures using, for example, molecular beam epitaxy and metal–organic vapor phase epitaxy, their characterization, and their use in heterojunctions, quantum wells, and high electron mobility transistors are reviewed.

    3. Progress toward biologically produced Biodegradable Thermoplastics (pages 30–37)

      Dr. Yves Poirier, Prof. Douglas E. Dennis, Dr. Christiane Nawrath and Prof. Chris Somerville

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050105

      Genetically-engineered bacteria which produce biodegradable polymers and copolymers with structures which depend on the culture in which they are kept are receiving increasing attention. Up to 90% of the dry weight of the bacteria can be intracellular granules of the plastic (see Figure), and the properties of the polymers can be controlled by varying the carbon-based nutrition of the bacteria. Recent advances are reviewed, including the use of plants instead of bacteria.

  4. Communications

    1. Top of page
    2. Masthead
    3. Essay
    4. Reviews
    5. Communications
    6. Research News
    7. Talking Point
    8. Book Reviews
    1. Chemical vapor deposition of silicon carbide powders using pulsed CO2 Lasers (pages 38–40)

      Dr. Malte Scholz, Dr. Werner Fuß and Prof. Dr. Karl-Ludwig Kompa

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050106

      A carbosilane polymer which survives temperatures up to 2000°C is reported. It deposits on the surface of SiC particulates which form during the laser pyrolysis of tetramethylsilane, and has possible applications as a sintering aid for SiC or in reducing brittleness in ceramic composites. Powders consisting of 8–10 nm SiC crystallites embedded in the carbosilane polymer are produced in the plasma formed by a focused CO2 laser.

    2. Large changes in optical response through chemical pre-ordering of poly(p-phenylenevinylene) (pages 40–43)

      David A. Halliday, Dr. Paul L. Burn, Dr. Donal D. C. Bradley, Dr. Richard H. Friend, Dr. Olaf M. Gelsen, Andrew B. Holmes, Dr. Arno Kraft, Dr. Josef H. F. Martens and Karl Pichler

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050107

      Conjugated polymers such as poly(p-phenylenevinylene), (PPV, see Figure), show real promise in optoelectronic applications. A new synthetic route to improved PPV is presented, involving the thermal conversion of a precursor polymer containing rigid rod conjugated segments joined by flexible spacer groups. A high degree of interchain ordering results which influences the optical response of the material.

    3. Mesophase formation in α-sexithienyl at high temperature—an X-ray diffraction study (pages 43–45)

      Dr. Silvia Destri, Dr. Marco Mascherpa and William Porzio

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050108

      The formation of a mesophase in α-sexithienyl is reported which cannot be identified as either a nematic or smectic phase. On heating, it is also shown that, through careful control of the reaction conditions, crystalline polythiophene comparable in quality with that prepared by electrosynthesis or other synthetic methods can be obtained. The materials are studied using high-temperature X-ray diffraction and differential scanning calorimetry.

    4. The synthesis and crystal structure of a liquid-crystalline ester of 4-carboxyphenylferrocene (pages 45–47)

      Christa Loubser, Dr. Christopher Imrie and Prof. Petrus H. van Rooyen

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050109

      Incorporation of ferrocene into a liquid crystal (see Figure) results in a material which offers the potential combination of the properties of an enantiotropic liquid crystal with NLO or magnetic activity. The compound demonstrates that monosubstituted ferrocene can be used to stabilize liquid crystal phases. Its LC properties and its X-ray structure are discussed.

    5. High surface area silica xerogels produced using triethoxysilane under non-supercritical conditions. Molecular hydrogen proposed as the high surface area promoter (pages 47–49)

      Prof. James M. Tour and Cynthia M. Kafka

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050110

      High surface area inorganic oxides find applications as absorbants, fillers, supports, reinforcing agents, and thermal, electrical, and photonic insulators. Supercritical drying, the removal of liquid from the gel pores by heating beyond the critical temperature and pressure of the liquid, is usually a required process step in the production of xerogels based on these materials. Here, an alternative method, not requiring supercritical drying, is presented.

    6. Polymer-mediated crystallization of inorganic solids: Calcite nucleation on poly(organosiloxane) surfaces (pages 49–51)

      Dr. Brian J. Brisdon, Dr. Brigid R. Heywood, Dr. Annabelle G. W. Hodson, Prof. Stephen Mann and Dr. Kim K. W. Wong

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050111

      The controlled deposition of inorganic crystalline solids at polymeric surfaces is of considerable technological and biological interest. Advantages of such inorganic–polymeric metrices are their enhanced thermal and chemical stability, an important factor in the future design of polymer–ceramic composites. The coral-like growths of calcium silicate shown in the Figure overgrow deposited calcite at high catalyst concentrations.

  5. Research News

    1. Top of page
    2. Masthead
    3. Essay
    4. Reviews
    5. Communications
    6. Research News
    7. Talking Point
    8. Book Reviews
    1. Imaging individual particles in concentrated colloidal dispersions by confocal scanning light microscopy (pages 52–54)

      Dr. Alfons van Blaaderen

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050112

      The study of colloidal dispersions is important in many areas, such as ceramics and electrorheological liquid research. Techniques such as high-resolution electron microscopy, which must be used in a vacuum, and light microscopy with its lower resolution and the fact that out-of-focus information contributes to the image have severe limitations in this work, many of which are avoided through the use of confocal scanning light microscopy. The pros and cons of the technique and its applications are discussed.

    2. Self-assembly of semiconductor nanocrystals (pages 55–57)

      Dr. Abraham Ulman

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050113

      The chemisorption of CdS nanocrystals (see Figure) on metal surfaces using alkylthiol monolayers has recently been demonstrated. The significance of this new aspect of self-organization phenomena in the study of monodispersed clusters and their possible applications are discussed.

    3. A novel metal-containing polymer: Poly(germanium enolate) (pages 57–59)

      Prof. Shiro Kobayashi and Dr. Shin-ichiro Shoda

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050114

      Germanium-containing polymers based on metal enolates have in the past not been synthesized due to the difficulty in obtaining stable enolates and to the fact that traditional preparation routes were geared to the production of monomeric species. A method for preparing these technologically interesting organometallic polymers is presented and discussed.

  6. Talking Point

    1. Top of page
    2. Masthead
    3. Essay
    4. Reviews
    5. Communications
    6. Research News
    7. Talking Point
    8. Book Reviews
    1. Is there a colloid in every solution-processable conducting polymer? (pages 60–62)

      Dr. Mahmoud Aldissi

      Article first published online: 29 OCT 2004 | DOI: 10.1002/adma.19930050115

      Quite often there is confusion regarding the definition of a solution, especially when conducting polymers are being discussed. Solvents containing particles with sizes below that of the wavelength of visible light will appear to be clear solutions but of course are not. This question has great significance in the definition of these materials and their study and processing.

  7. Book Reviews

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

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