Advanced Materials

Cover image for Vol. 13 Issue 12‐13

July, 2001

Volume 13, Issue 12-13

Pages 861–1038

    1. Materials Research in Australia and New Zealand (pages 861–863)

      S. A. Bagshaw, A. R. Hayman and P. Mulvaney

      Version of Record online: 28 JUN 2001 | DOI: 10.1002/1521-4095(200107)13:12/13<861::AID-ADMA861>3.0.CO;2-N

      An overview of current materials research in Australia and New Zealand is provided through the contributions that make up this special double issue of Advanced Materials. The history, current status, and driving forces behind materials research in these two countries are highlighted by the guest editors of this issue, and a summary of the topics covered is presented. The reasons why these two countries have taken different research directions are also commented on.

    2. Materials Science and Innovation in New Zealand (pages 865–867)

      P. C. Hodgson

      Version of Record online: 28 JUN 2001 | DOI: 10.1002/1521-4095(200107)13:12/13<865::AID-ADMA865>3.0.CO;2-7

      Two-thirds of research and development activities in New Zealand are funded by the government. The Minister of Research, Science, and Technology, the Honorable Pete Hodgson, explains why. Not just science policy is discussed in his essay, also many examples of New Zealand's finest materials science research are mentioned. The interlinking of economy, politics, and research, as well as the way forward towards a flourishing global presence in the future, are discussed.

    3. Investment in Research in Australia: The Role of the Australian Research Council (pages 869–872)

      V. Sara

      Version of Record online: 28 JUN 2001 | DOI: 10.1002/1521-4095(200107)13:12/13<869::AID-ADMA869>3.0.CO;2-S

      The Australian Research Council (ARC)is Australia's main funding body for basic research. The government's recent innovation action plan “Backing Australia's Ability” has strengthened the ARC's key role in providing support for fundamental research, university/industry linkage, and international cooperation. Detailed figures on the funding of materials science through grants and the support of research centers by the ARC are given.

    4. Role of CSIRO in Australian Science (pages 873–875)

      C. Adam

      Version of Record online: 28 JUN 2001 | DOI: 10.1002/1521-4095(200107)13:12/13<873::AID-ADMA873>3.0.CO;2-B

      The Commonwealth Scientific and Industrial Research Organisation (CSIRO) was created as a national scientific research institution that would undertake research for the benefit of Australia's primary and secondary industries. For more than 70 years now it has provided the know-how for revamping and modernizing traditional Australian industries and for establishing new industries, such as biotechnology and information technology. A summary of the organization's extensive list of achievements is given in this essay.

    5. Nanolithography in the Evanescent Near Field (pages 877–887)

      M. M. Alkaisi, R. J. Blaikie and S. J. McNab

      Version of Record online: 28 JUN 2001 | DOI: 10.1002/1521-4095(200107)13:12/13<877::AID-ADMA877>3.0.CO;2-W

      Structures with periods as small as 140 nm can be created employing evanescently decaying components combined with ultrathin resists in optical lithography. The technique, called ENFOL (evanescent near-field optical lithography) (see Figure), its applications, and simulations of the process are unraveled in this review. ENFOL promises the high-throughput, low-cost, nanometer-scale patterning of large areas.

    6. Inorganic Chiral Optical Materials (pages 889–897)

      I. Hodgkinson and Q. h. Wu

      Version of Record online: 28 JUN 2001 | DOI: 10.1002/1521-4095(200107)13:12/13<889::AID-ADMA889>3.0.CO;2-K

      Vacuum-deposited inorganic materials with a chiral nanostructure (see Figure) show large optical activity and are useful for a variety of optical devices. The authors give an overview of current chiral deposition technology, optical properties of different materials, and important applications, as well as an outlook on future developments in the field.

    7. Controlled Synthesis and Modification of Carbon Nanotubes and C60: Carbon Nanostructures for Advanced Polymeric Composite Materials (pages 899–913)

      L. Dai and A. W. H. Mau

      Version of Record online: 28 JUN 2001 | DOI: 10.1002/1521-4095(200107)13:12/13<899::AID-ADMA899>3.0.CO;2-G

      Carbon nanostructures and C60 fullerenes show unique properties, which make these structures ideally suited for the fabrication of advanced composite materials (see Figure). Synergetic effects with polymers along with advanced methods for microstructuring these composite materials are important issues that are discussed in this article.

    8. Conjugated Polymers for Light-Emitting Applications (pages 915–925)

      L. Dai, B. Winkler, L. Dong, L. Tong and A. W. H. Mau

      Version of Record online: 28 JUN 2001 | DOI: 10.1002/1521-4095(200107)13:12/13<915::AID-ADMA915>3.0.CO;2-N

      Processable conjugated polymers such as those shown in the Figure are highly desirable for applications in, for example, light-emitting devices, especially electrochemical light-emitting cells. Here recent progress in Australia on the synthesis and device applications of such polymers is reviewed and the possibility of tuning the emitted color via an intercalation-induced conformational change of the polymer backbone is examined.

    9. Systematic Conductivity Behavior in Conducting Polymers: Effects of Heterogeneous Disorder (pages 927–941)

      A. B. Kaiser

      Version of Record online: 28 JUN 2001 | DOI: 10.1002/1521-4095(200107)13:12/13<927::AID-ADMA927>3.0.CO;2-B

      The conduction process in conducting polymers has some unusual features. Even for highly conducting samples, the electronic transport properties show a mixture of metallic and non-metallic character, and is explained here in terms of the heterogeneous morphology of the polymers. The Figure shows the characteristic temperature dependence of conductivity as the doping level is increased.

    10. Novel Lithium-Ion Cathode Materials Based on Layered Manganese Oxides (pages 943–956)

      B. Ammundsen and J. Paulsen

      Version of Record online: 28 JUN 2001 | DOI: 10.1002/1521-4095(200107)13:12/13<943::AID-ADMA943>3.0.CO;2-J

      Stabilization of the layered crystal structure of lithium manganese oxide is important since this material represents an attractive low-cost alternative to lithium cobalt oxide—typically used in lithium-ion batteries. Work towards this end is reviewed in this article as is the use of layered manganese oxide (see Figure) as a base for developing novel solid–solution cathode materials with improved capacity, cycling stability, and safety.

    11. Plastic Crystal Electrolyte Materials: New Perspectives on Solid State Ionics (pages 957–966)

      D. R. MacFarlane and M. Forsyth

      Version of Record online: 28 JUN 2001 | DOI: 10.1002/1521-4095(200107)13:12/13<957::AID-ADMA957>3.0.CO;2-#

      Plastic crystals of quaternary pyrrolidinium saltsare promising materials for solid electrolytes in lithium batteries. Their conductivity, caused by crystal defects and high local ion mobility, can be increased drastically by doping with lithium ions. The Figure illustrates the revolving door mechanism proposed for the transport of Li+ through a matrix of rotating SO42– ions.

    12. Formation of Lyotropic Liquid Crystals at the Graphite/Aqueous Solution Interface (pages 967–970)

      P. A. FitzGerald and G. G. Warr

      Version of Record online: 28 JUN 2001 | DOI: 10.1002/1521-4095(200107)13:12/13<967::AID-ADMA967>3.0.CO;2-W

      The self-assembly of quaternary ammonium salt surfactantson the cleavage plane of graphite has been investigated by direct imaging using AFM and force curves. It is shown that the graphite surface orients the first adsorbate layer into stripes of hemicylindrical micelles (see Figure for a schematic picture). From there, a hexagonal array of cylindrical liquid crystal stripes builds up at higher surfactant concentration.

    13. Direct Evidence of Two Types of UV-Induced Glass Changes in Silicate-Based Optical Fibers (pages 970–973)

      J. Canning, K. Sommer, M. Englund and S. Huntington

      Version of Record online: 28 JUN 2001 | DOI: 10.1002/1521-4095(200107)13:12/13<970::AID-ADMA970>3.0.CO;2-J

      Two spatially distinct types of UV-induced refractive index changes in phosphosilicate glass fibers have been differentiated by the authors. The index change close to the core-cladding interface is less stable than the index change in the bulk fiber core. It is shown that by using presensitization techniques, in which the use of hydrogen is minimized so as to optimize the index changes possible within the core center, gratings of better stability than those prepared in fully hydrogen-loaded optical fiber are obtained.

    14. Novel Colloidal Materials for High-Throughput Screening Applications in Drug Discovery and Genomics (pages 975–979)

      M. Trau and B. J. Battersby

      Version of Record online: 28 JUN 2001 | DOI: 10.1002/1521-4095(200107)13:12/13<975::AID-ADMA975>3.0.CO;2-#

      Tracking the reaction historyis the means of choice to identify bioactive compounds in large combinatorial libraries. The authors describe two approaches to synthesis on silica beads: (a) addition of a “reporter dye tag” during each synthesis step (see Figure), which attaches itself to the bead by colloidal forces, and (b) encapsulating arrays of fluorescent dyes into the beads to encode them uniquely, for recognition with a flow cytometer after each reaction step.

    15. Advanced Materials for Banknote Applications (pages 980–984)

      B. Hardwick, W. Jackson, G. Wilson and A. W. H. Mau

      Version of Record online: 28 JUN 2001 | DOI: 10.1002/1521-4095(200107)13:12/13<980::AID-ADMA980>3.0.CO;2-F

      Australia's leading position in the worldwide defense against currency counterfeiters became evident when the country introduced polymer banknotes with transparent windows in 1988. The authors outline the historic development of the polymer banknote and report recent innovations at CSIRO and Note Printing Australia, who are working together to develop anti-counterfeiting features, such as self-verifying banknotes (see Figure and cover).

    16. Synthesis of Tunable, Highly Luminescent QD-Glasses Through Sol-Gel Processing (pages 985–988)

      S. T. Selvan, C. Bullen, M. Ashokkumar and P. Mulvaney

      Version of Record online: 28 JUN 2001 | DOI: 10.1002/1521-4095(200107)13:12/13<985::AID-ADMA985>3.0.CO;2-W

      Photostable quantum dot (QD) glasses for uses in optical devices (see Figure) are prepared here by solution-phase synthesis of the luminescent material followed by sol–gel processing, to embed the semiconductor particles in silica. Surface reactions degrading the QD are prevented by adding octylamine, which passivates the surface and accelerates the gelation process. ZnS-capped CdSe QDs thus treated remain luminescent over several months.

    17. Probing Material Formation in the Presence of Organic and Biological Molecules (pages 989–992)

      K. M. McGrath

      Version of Record online: 28 JUN 2001 | DOI: 10.1002/1521-4095(200107)13:12/13<989::AID-ADMA989>3.0.CO;2-G

      Mimicking biomineralization in vitromay become a way to access crystalline inorganic materials with useful microstructures. The approach described here involves crystallization of calcium carbonate in the presence of sea urchin proteins, and gives rise to microporous crystals. The influence of organic molecules on crystal growth (see Figure) is also demonstrated.

    18. Ceramic Membrane Technologies for Oxygen Separation (pages 993–996)

      S. P. S. Badwal and F. T. Ciacchi

      Version of Record online: 28 JUN 2001 | DOI: 10.1002/1521-4095(200107)13:12/13<993::AID-ADMA993>3.0.CO;2-#

      Metal oxide membranes that selectively transport O2– ions are the most effective means of oxygen separation. While one design, with a mere oxide ion conductor, achieves O2 purification electrochemically (see Figure), a second type, using an O2–- and electron-conducting membrane material, directly uses the oxide ions as reactant in fuel cell-type applications for conversion of natural gas to syn-gas (CO + H2).

    19. Shallow Nanoporous Surface Layers Produced by Helium Ion Implantation (pages 997–1000)

      P. B. Johnson, A. Markwitz and P. W. Gilberd

      Version of Record online: 28 JUN 2001 | DOI: 10.1002/1521-4095(200107)13:12/13<997::AID-ADMA997>3.0.CO;2-K

      High-dose helium implantation of metals can result in the formation of nanoporous bubble structures with striking features. These structures, which may be a universal response for all metals implanted under appropriate conditions, show considerable promise for applications such as catalysis. The Figure shows a bright-field TEM micrograph of a nanoporous bubble structure in helium-ion-implanted vanadium.

    20. Nano- and Microcrystal Coatings and Their High-Temperature Applications (pages 1001–1004)

      W. Gao, Z. Liu and Z. Li

      Version of Record online: 28 JUN 2001 | DOI: 10.1002/1521-4095(200107)13:12/13<1001::AID-ADMA1001>3.0.CO;2-V

      Nanocrystalline alloy coatingsare superior to their bulk analogues in high-temperature applications, since they are easily selectively oxidized to form a protective oxide scale that prevents high-temperature corrosion. Also, the nanocrystalline alloy body counteracts spallation of the oxide scale. The Figure shows an AFM image of an electro-spark deposited Al coating on stainless steel.

    21. Rewritable 3D Bit Optical Data Storage in a PMMA-Based Photorefractive Polymer (pages 1005–1007)

      D. Day, M. Gu and A. Smallridge

      Version of Record online: 28 JUN 2001 | DOI: 10.1002/1521-4095(200107)13:12/13<1005::AID-ADMA1005>3.0.CO;2-7

      A cheap, compact, and rewritable high-density optical data storage system for CD and DVD applications is presented by the authors. Continuous-wave illumination under two-photon excitation in a new poly(methylmethacrylate) (PMMA) based photorefractive polymer allows 3D bit storage of sub-Tbyte data. The Figure shows an area of such a polymer that has been written, erased, and rewritten.

    22. Nanopowders Synthesized by Mechanochemical Processing (pages 1008–1010)

      P. G. McCormick, T. Tsuzuki, J. S. Robinson and J. Ding

      Version of Record online: 28 JUN 2001 | DOI: 10.1002/1521-4095(200107)13:12/13<1008::AID-ADMA1008>3.0.CO;2-Q

      Ultrafine powdersconsisting of nanometer-sized grains (down to 4 nm) can be synthesized economically by mechanically activated solid-state reactions, followed by removal of soluble by-products. The milling enlarges the active surface and enables reactions that typically require strong heating to proceed at ambient temperature. The Figure shows CeO2 particles 8 nm in diameter that have been produced in this manner.

    23. Super-Microporous Silicate Molecular Sieves (pages 1011–1013)

      S. A. Bagshaw and A. R. Hayman

      Version of Record online: 28 JUN 2001 | DOI: 10.1002/1521-4095(200107)13:12/13<1011::AID-ADMA1011>3.0.CO;2-T

      A new synthesis of supermicroporous silica(1.6–2.0 nm diameter), using micelles of a quaternary ω-hydroxyalkylammonium salt, that exhibits highly ordered pore arrays (see Figure) is presented by the authors. Details on the synthesis and pore size determination by adsorption techniques are given. In an outlook, the effects of template chain length and Al or Ti doping (catalytic centers) on pore size and array stability are discussed.

    24. Silica Fiber Poling Technology (pages 1014–1018)

      W. Xu, P. Blazkiewicz and S. Fleming

      Version of Record online: 28 JUN 2001 | DOI: 10.1002/1521-4095(200107)13:12/13<1014::AID-ADMA1014>3.0.CO;2-B

      Cutting-edge materials science leading to a myriad of silica fiber components and waveguide circuits is possible thanks to the technology described in this article. The authors use a poling technique to induce useable second-order nonlinear and linear electro-optic coefficients in silica fibers. The three most commonly used methods, i.e., thermal poling, CO2 laser-assisted poling, and UV poling, are thoroughly described and explained, not to mention the inexhaustible range of applications.

    25. Crystalline Silicon Photovoltaic Cells (pages 1019–1022)

      M. A. Green

      Version of Record online: 28 JUN 2001 | DOI: 10.1002/1521-4095(200107)13:12/13<1019::AID-ADMA1019>3.0.CO;2-I

      Solar cells with 25 % efficiency have been fabricated and the structure is shown in the Figure. Silicon cells are expected to be able to satisfy the ever-growing demand for solar photovoltaic energy. The silicon cell fabrication as well as the latest advances in solar cell technology are discussed in this article.

    26. Thin-Film Amorphous Silicon Position-Sensitive Detectors (pages 1022–1026)

      J. Henry and J. Livingstone

      Version of Record online: 28 JUN 2001 | DOI: 10.1002/1521-4095(200107)13:12/13<1022::AID-ADMA1023>3.0.CO;2-I

      The optical response of amorphous silicon sensors to white and red light has been investigated. The Figure shows the configuration of a crystalline position-sensitive detector for measurement in photovoltaic mode. Three different structures have been studied and the results are reported in this article.

    27. Nitridation of Silicon Oxide Layers Studied with Ion Beam Analysis on the Nanometer Scale (pages 1027–1030)

      A. Markwitz and G. V. White

      Version of Record online: 28 JUN 2001 | DOI: 10.1002/1521-4095(200107)13:12/13<1027::AID-ADMA1027>3.0.CO;2-S

      How does high-temperature nitridation of the SiO2 layer on Si wafers proceed? Elemental depth profiling by ion beam analysis (IBA) techniques reveals that N uptake increases with temperature and—unexpectedly—with SiO2 layer thickness. The Figure shows a nitridation spot on silica, whose center is surrounded by a ring of the initial product, silicon oxynitride Si2N2O.

    28. Amorphous Thin Films: Insulators, Metals, and Semiconductors (pages 1031–1033)

      H. J. Trodahl and A. Bittar

      Version of Record online: 28 JUN 2001 | DOI: 10.1002/1521-4095(200107)13:12/13<1031::AID-ADMA1031>3.0.CO;2-P

      Amorphous thin films widely resemble crystalline films in their properties, but exhibit more defect-related electronic states and (often adverse) effects. Highly ordered amorphous films (see Figure) can be generated by ion- assisted deposition (IAD) as demonstrated for the wide-bandgap semiconductor GaN, in which no mid-gap electronic states have been detected.

    29. Probing Solid–Solution Interfacial Chemistry with ATR-IR Spectroscopy of Particle Films (pages 1034–1038)

      A. J. McQuillan

      Version of Record online: 28 JUN 2001 | DOI: 10.1002/1521-4095(200107)13:12/13<1034::AID-ADMA1034>3.0.CO;2-7

      IR spectroscopy of thin particle films,deposited on an attenuated total reflection (ATR) crystal and still immersed in solution, has high potential for investigating the chemistry of solid–solution interfaces (see Figure for principle). As highlighted in this article, phenomena that can be studied include pH-dependent adsorption, photosensitization, photocatalysis, and biocompatibility of prosthetic materials.