Advanced Materials

Cover image for Vol. 19 Issue 6

March, 2007

Volume 19, Issue 6

Pages 771–894

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Communications
    6. Research News
    7. Index
    1. Cover Picture: Weaving Genetically Engineered Functionality into Mechanically Robust Virus Fibers (Adv. Mater. 6/2007)

      C.-Y. Chiang, C. M. Mello, J. Gu, E. C. C. M. Silva, K. J. Van Vliet and A. M. Belcher

      Article first published online: 9 MAR 2007 | DOI: 10.1002/adma.200790021

      Functionality-tunable fibers fabricated from the M13 virus are found to have mechanical toughness and strength comparable to synthetic homopolymer fibers. The desired functionality can be programmed by manipulating the virus genome (see figure and cover). The tunable functionalities and mechanical properties of the virus fibers show the promise of various applications.

  2. Inside Front Cover

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Communications
    6. Research News
    7. Index
    1. Inside Front Cover: Homeotropic Alignment of Columnar Liquid Crystals in Open Films by Means of Surface Nanopatterning (Adv. Mater. 6/2007)

      R. I. Gearba, D. V. Anokhin, A. I. Bondar, W. Bras, M. Jahr, M. Lehmann and D. A. Ivanov

      Article first published online: 9 MAR 2007 | DOI: 10.1002/adma.200790022

      Columnar liquid crystals (LCs) are reported to align spontaneously homeotropically—that is, orthogonally to the surface (see figure and inside cover)—on a glass surface covered with a layer of poly(tetrafluoroethylene) transferred by friction (rubbing). This strategy for producing macroscopic monodomains of homeotropically aligned LCs may find important applications in the fabrication of LC-based organic solar cells.

  3. Contents

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Communications
    6. Research News
    7. Index
    1. Contents: Adv. Mater. 6/2007 (pages 771–779)

      Article first published online: 9 MAR 2007 | DOI: 10.1002/adma.200790019

  4. Communications

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Communications
    6. Research News
    7. Index
    1. Piezoelectric Gated Diode of a Single ZnO Nanowire (pages 781–784)

      J. H. He, C. L. Hsin, J. Liu, L. J. Chen and Z. L. Wang

      Article first published online: 13 FEB 2007 | DOI: 10.1002/adma.200601908

      Thumbnail image of graphical abstract

      A ZnO nanowire behaves like a rectifier under bending strain, as demonstrated by its current–voltage characteristics (see graph). This is interpreted with the consideration of a piezoelectricity-induced potential energy barrier at the interface of the conductive tip and nanowire (see schematic). Under appropriate bending and voltage control, each NW could correspond to a device element for random-access-memory, diode, and force-sensor applications.

    2. High-Performance Ceramic Membranes with a Separation Layer of Metal Oxide Nanofibers (pages 785–790)

      X. B. Ke, H. Y. Zhu, X. P. Gao, J. W. Liu and Z. F. Zheng

      Article first published online: 19 FEB 2007 | DOI: 10.1002/adma.200601984

      Thumbnail image of graphical abstract

      Layers of randomly oriented fibers arranged in a hierarchical structure as the separation layer in ceramic membranes (see figure) are shown to greatly improve the separation efficiency compared to conventionally fabricated ceramic membranes, and remove the problems of cracks, pinholes, and serious sintering. The membranes have many potential applications, for example, removing viruses and waterborne pathogens.

      Corrected by:

      Correction: High-Performance Ceramic Membranes with a Separation Layer of Metal Oxide Nanofibers

      Vol. 19, Issue 24, 4325, Article first published online: 11 DEC 2007

    3. Woodpile Metallic Photonic Crystals Fabricated by Using Soft Lithography for Tailored Thermal Emission (pages 791–794)

      J.-H. Lee, Y.-S. Kim, K. Constant and K.-M. Ho

      Article first published online: 19 FEB 2007 | DOI: 10.1002/adma.200602550

      Thumbnail image of graphical abstract

      Woodpile metallic photonic crystals are fabricated by using soft lithography and electrodeposition (see figure) for tailored thermal emission. This method produces a highly layered full-metallic structure with excellent structural fidelity. By adding a homogeneous monolithic backplane to the conventional woodpile structure, the difficulty of alignment in layer-by-layer fabrication is alleviated, while preserving characteristic enhanced thermal emission.

    4. Direct Printing of Bioceramic Implants with Spatially Localized Angiogenic Factors (pages 795–800)

      U. Gbureck, T. Hölzel, C. J. Doillon, F. A. Müller and J. E. Barralet

      Article first published online: 27 FEB 2007 | DOI: 10.1002/adma.200601370

      Thumbnail image of graphical abstract

      Direct printing of brushite and hydroxyapatite bioceramics at room temperature is used to construct model implants onto which the angiogenic compounds vascular endothelial growth factor (VEGF) and copper sulfate were adsorbed. This low-temperature direct approach offers several practical advantages and may find application in bone grafting. The figure shows examples of complex shapes made of brushite.

    5. Direct Fabrication of Microlens Arrays with Polarization Selectivity (pages 801–804)

      M. Yaegashi, M. Kinoshita, A. Shishido and T. Ikeda

      Article first published online: 9 MAR 2007 | DOI: 10.1002/adma.200601329

      Thumbnail image of graphical abstract

      Fabrication of microlens arrays (see figure) is explored using photoinduced reorientation of dye-doped liquid crystals and successive photopolymerization with a single laser beam by selecting a suitable photoinitiator. Each microlens in the microlens array exhibits polarization selectivity with respect to the incident polarized light, and the arrays can be arranged in desired patterns and with desired polarization directions.

    6. Melt-Processing of Conjugated Liquid Crystals: A Simple Route to Fabricate OFETs (pages 805–809)

      J. C. Maunoury, J. R. Howse and M. L. Turner

      Article first published online: 9 MAR 2007 | DOI: 10.1002/adma.200602859

      Thumbnail image of graphical abstract

      Melt-processing of 5,5′-bis(4-hexylphenyl)-2,2′-bithiophene leads to a favorable morphology of the conjugated liquid crystal in the channel of an OFET (see figure) and a fivefold improvement of the mobility over that found for conventional devices fabricated by evaporation. This process does not require solvents or vacuum-deposition processes.

    7. Polymer Light-Emitting Diodes with Cathodes Printed from Conducting Ag Paste (pages 810–814)

      W. J. Zeng, H. B. Wu, C. Zhang, F. Huang, J. B. Peng, W. Yang and Y. Cao

      Article first published online: 9 MAR 2007 | DOI: 10.1002/adma.200602567

      Thumbnail image of graphical abstract

      All-printable polymer light-emitting diodes (PLEDs) are realized by the development of a new bilayer cathode that combines Ag paste with aminoalkyl- substituted polyfluorenes. PLEDs with a printed Ag-paste cathode (see figure) show comparable device performance to those devices incorporating a low-work-function cathode (Ba/Al) that is deposited thermally.

    8. Homeotropic Alignment of Columnar Liquid Crystals in Open Films by Means of Surface Nanopatterning (pages 815–820)

      R. I. Gearba, D. V. Anokhin, A. I. Bondar, W. Bras, M. Jahr, M. Lehmann and D. A. Ivanov

      Article first published online: 9 MAR 2007 | DOI: 10.1002/adma.200602460

      Thumbnail image of graphical abstract

      Columnar liquid crystals (LCs) are reported to align spontaneously homeotropically—that is, orthogonally to the surface (see figure and inside cover)—on a glass surface covered with a layer of poly(tetrafluoroethylene) transferred by friction (rubbing). This strategy for producing macroscopic monodomains of homeotropically aligned LCs may find important applications in the fabrication of LC-based organic solar cells.

    9. Multifilament Fibers Based on Dissolution of Cellulose in NaOH/Urea Aqueous Solution: Structure and Properties (pages 821–825)

      J. Cai, L. Zhang, J. Zhou, H. Qi, H. Chen, T. Kondo, X. Chen and B. Chu

      Article first published online: 22 FEB 2007 | DOI: 10.1002/adma.200601521

      Thumbnail image of graphical abstract

      High-quality cellulose multifilaments (see figure) are spun using a preliminary pilot apparatus, from the cellulose dope in an NaOH and urea aqueous solution precooled to –12 °C, by using a low-cost, simple, and environmentally friendly process. Small-angle X-ray scattering patterns indicate that the orientation of the multifilaments increase with a drawing process, leading to the improvement of their tensile strength.

    10. Weaving Genetically Engineered Functionality into Mechanically Robust Virus Fibers (pages 826–832)

      C.-Y. Chiang, C. M. Mello, J. Gu, E. C. C. M. Silva, K. J. Van Vliet and A. M. Belcher

      Article first published online: 19 FEB 2007 | DOI: 10.1002/adma.200602262

      Thumbnail image of graphical abstract

      Functionality-tunable fibers fabricated from the M13 virus are found to have mechanical toughness and strength comparable to synthetic homopolymer fibers. The desired functionality can be programmed by manipulating the virus genome (see figure and cover). The tunable functionalities and mechanical properties of the virus fibers show the promise of various applications.

    11. High Carrier Mobility Polythiophene Thin Films: Structure Determination by Experiment and Theory (pages 833–837)

      D. M. DeLongchamp, R. J. Kline, E. K. Lin, D. A. Fischer, L. J. Richter, L. A. Lucas, M. Heeney, I. McCulloch and J. E. Northrup

      Article first published online: 19 FEB 2007 | DOI: 10.1002/adma.200602651

      Thumbnail image of graphical abstract

      The structure within crystalline thin films of a high-carrier-mobility polythiophene is studied with complementary characterization methods and first-principles theory. As shown in the figure, two important structural aspects are revealed: 1) a slip in the face-to-face π-π packing, which strongly influences carrier mobility, and 2) the interdigitation of highly trans side chains between vertically adjacent lamellae.

    12. Nd2O3 Nanoparticles Modified with a Silane-Coupling Agent as a Liquid Laser Medium (pages 838–842)

      R. B. Yu, K. H. Yu, W. Wei, X. X. Xu, X. M. Qiu, S. Liu, W. Huang, G. Tang, H. Ford and B. Peng

      Article first published online: 19 FEB 2007 | DOI: 10.1002/adma.200600936

      Thumbnail image of graphical abstract

      Efficient lasing is demonstrated from a clear dispersion of silane-modifed Nd2O3nanoparticles in dimethylsulfoxide. Surface modification with the silane helps to disperse the nanoparticles, as indicated in the figure. The fluorescence lifetime and quantum yield of the dispersed nanoparticles are amongst the highest obtained for a NdIII emitting center dispersed in an organic medium.

    13. A General Route to Printable High-Mobility Transparent Amorphous Oxide Semiconductors (pages 843–847)

      D.-H. Lee, Y.-J. Chang, G. S. Herman and C.-H. Chang

      Article first published online: 19 FEB 2007 | DOI: 10.1002/adma.200600961

      Thumbnail image of graphical abstract

      A general low-cost method for ink-jet printing transparent amorphous oxide semiconductors (see figure) is presented. The process uses metal halide precursors dissolved in acetonitrile, and this precursor solution is capable of forming a uniform and continuous metal halide thin film over a large area through both ink-jet printing and blanket-coating techniques.

    14. Conducting-Polymer/Iron-Redox- Couple Composite Cathodes for Lithium Secondary Batteries (pages 848–851)

      K.-S. Park, S. B. Schougaard and J. B. Goodenough

      Article first published online: 19 FEB 2007 | DOI: 10.1002/adma.200600369

      Thumbnail image of graphical abstract

      Physically or chemically attaching an FeIII/FeIIredox couple to the backbone of a conducting polymer leads to stabilization of the charge/discharge characteristics and higher electrode capacities. Composite cathodes made from LiFePO4 particles bound to polypyrrole show enhanced electrode capacities and better rate capabilities, as shown in the figure. Chemically attaching ferrocene to the pyrrole backbone not only stabilizes the charge–discharge curves but also leads to higher capacity.

    15. Giant Dielectric Permittivities in Functionalized Carbon-Nanotube/ Electroactive-Polymer Nanocomposites (pages 852–857)

      Z.-M. Dang, L. Wang, Y. Yin, Q. Zhang and Q.-Q. Lei

      Article first published online: 19 FEB 2007 | DOI: 10.1002/adma.200600703

      Thumbnail image of graphical abstract

      Trifluorophenyl-functionalized multi-walled-carbon-nanotube/poly(vinylidene fluoride) (TFP-MWNT/PVDF) nanocomposites are fabricated by employing a wet-chemistry route. The modified MWNTs are observed to form a well-dispersed, structurally random nanophase within the polymer matrix (see figure). The TFP-MWNT/PVDF nanocomposite exhibits enhanced dielectric permittivity when the content of TFP-MWNT is close to the percolation threshold.

    16. Self-Assembly of a Dipeptide- Containing Conformationally Restricted Dehydrophenylalanine Residue to Form Ordered Nanotubes (pages 858–861)

      M. Gupta, A. Bagaria, A. Mishra, P. Mathur, A. Basu, S. Ramakumar and V. S. Chauhan

      Article first published online: 19 FEB 2007 | DOI: 10.1002/adma.200601774

      Thumbnail image of graphical abstract

      The self-assembly of a dehydrophenylalanine containing dipeptide (see figure), yielding highly ordered nanotubular structures, is discussed. The tubes are longer and thinner than previously reported peptide-based tubular structures; they are stable to boiling-water temperatures, different pH conditions, and to a highly nonspecific protease (Proteinase K).

    17. 3-(9-Carbazolyl)carbazoles and 3,6-Di(9-carbazolyl)carbazoles as Effective Host Materials for Efficient Blue Organic Electrophosphorescence (pages 862–866)

      M.-H. Tsai, Y.-H. Hong, C.-H. Chang, H.-C. Su, C.-C. Wu, A. Matoliukstyte, J. Simokaitiene, S. Grigalevicius, J. V. Grazulevicius and C.-P. Hsu

      Article first published online: 9 MAR 2007 | DOI: 10.1002/adma.200600822

      Thumbnail image of graphical abstract

      Linking topology in oligocarbazoles (see figure) has a strong influence on their electronic properties. 3(6),9′-linked oligocarbazoles exhibit unusual suppression of electronic coupling between units, leading to localized excited states and very small reduction of triplet energies (compared to the monomer). Coupled with their excellent morphological stability, this makes them suitable as host materials for blue electrophosphorescence devices.

    18. Incorporation of Water and Fast Proton Conduction in the Inherently Oxygen-Deficient Compound La26O27□(BO3)8 (pages 867–870)

      S. Noirault, S. Célérier, O. Joubert, M. T. Caldes and Y. Piffard

      Article first published online: 22 FEB 2007 | DOI: 10.1002/adma.200602033

      Thumbnail image of graphical abstract

      The monoclinic inherently oxygen- deficient compound La26O27□(BO3)8 can react with water vapor and incorporate protons by filling the oxygen-ion vacancy and forming hydroxide ions, leading to the oxy-hydroxy-borate La26O26(OH)2(BO3)8. This reaction is reversible. The conductivity measured under wet conditions at 300 °C is that of La26O26(OH)2(BO3)8; at 600 °C the proton contribution to the total conductivity is still clearly visible (see figure).

    19. Stereoblock Polypropylene as a Prototype Example of Elasticity via a Flip-Flop Reorientation of Crystals in a Compliant Matrix (pages 871–874)

      F. Auriemma, C. De Rosa and M. Corradi

      Article first published online: 9 MAR 2007 | DOI: 10.1002/adma.200601296

      Thumbnail image of graphical abstract

      Elastomeric polypropylene characterized by chains with an isotactic and atactic stereoblock structure shows elastic behavior in a large range of deformations notwithstanding the high degree of crystallinity, because of the occurrence of flip-flop reversible reorientation of crystals of the γ form that occur during stretching and the successive release of tension, as shown schematically in the figure.

    20. Magnetism in Polymers with Embedded Gold Nanoparticles (pages 875–877)

      J. de la Venta, A. Pucci, E. Fernández Pinel, M. A. García, C. de Julián Fernandez, P. Crespo, P. Mazzoldi, G. Ruggeri and A. Hernando

      Article first published online: 22 FEB 2007 | DOI: 10.1002/adma.200600984

      Thumbnail image of graphical abstract

      Magnetism can be induced in polymers by embedding thiol-capped Au nanoparticles (NPs). The capped NPs (see figure) induce an alteration in the electronic properties of Au, giving rise to ferromagnetic behavior despite the diamagnetic character of bulk Au. When the capped NPs are embedded into a polymeric matrix the magnetic properties are preserved, opening up the possibility of developing Au-based macroscopic magnetic materials.

    21. Heterogeneous Distribution of Reactivity on Metallic Biomaterials: Scanning Probe Microscopy Studies of the Biphasic Ti Alloy Ti6Al4V (pages 878–882)

      S. E. Pust, D. Scharnweber, C. Nunes Kirchner and G. Wittstock

      Article first published online: 13 FEB 2007 | DOI: 10.1002/adma.200601446

      Thumbnail image of graphical abstract

      Biphasic titanium alloys are preferred materials for load-bearing metallic implants such as artificial joints. A comprehensive understanding of the electron-transfer behavior of the native oxide layer on these materials is of great significance for improving the biocompatibility of such alloys. The combined use of different scanning probe techniques shows different electronic conductivities and electron-transfer properties of passive layers formed on α and β phases (see figure).

    22. The Role of Carboxylated Carbonaceous Fragments in the Functionalization and Spectroscopy of a Single-Walled Carbon-Nanotube Material (pages 883–887)

      C. G. Salzmann, S. A. Llewellyn, G. Tobias, M. A. H. Ward, Y. Huh and M. L. H. Green

      Article first published online: 13 FEB 2007 | DOI: 10.1002/adma.200601310

      Thumbnail image of graphical abstract

      The majority of carboxylic acid groups formed after treatment of a single-walled carbon nanotube (SWCNT) material with nitric acid are present on carboxylated carbonaceous fragments (CCFs) (see figure). These CCFs are removed from the SWCNTs by treatment with NaOH solution and identified as carriers of the COOH functionality, implying that previous reports claiming side-wall functionalization of the SWCNTs with COOH groups should be reconsidered.

  5. Research News

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Communications
    6. Research News
    7. Index
    1. Nanopiezotronics (pages 889–892)

      Z. L. Wang

      Article first published online: 27 FEB 2007 | DOI: 10.1002/adma.200602918

      Thumbnail image of graphical abstract

      The utilization of the coupled piezoelectric and semiconducting properties of nanowires and nanobelts is the fundamental principle of nanopiezotronics, which can be used for designing and fabricating electronic devices and components, such as field-effect transistors and diodes (see figure). The physics of nanopiezotronics is based on the principle of a nanowire nanogenerator that converts mechanical energy into electric energy.

  6. Index

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Communications
    6. Research News
    7. Index
    1. Author Index and Subject Index Adv. Mater. 6/2007 (pages 893–894)

      Article first published online: 9 MAR 2007 | DOI: 10.1002/adma.200790020

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