Advanced Materials

Cover image for Vol. 17 Issue 12

June, 2005

Volume 17, Issue 12

Pages 1451–1565

    1. Cover Picture: Synthesis of a Self-Assembled Hybrid of Ultrananocrystalline Diamond and Carbon Nanotubes (Adv. Mater. 12/2005)

      X. Xiao, J. W. Elam, S. Trasobares, O. Auciello and J. A. Carlisle

      Article first published online: 7 JUN 2005 | DOI: 10.1002/adma.200590061

      A self-assembled hybrid of ultrananocrystalline diamond (UNCD) and carbon nanotubes (CNTs) is successfully prepared by their simultaneous growth in an argon-rich Ar/CH4 plasma (see Figure and cover). Control of the relative fractions and configurations of UNCD and CNTs in the hybrid material is demonstrated. This new synthesis pathway enables the development of new nanocarbons with unique mechanical, tribological, and electrochemical properties.

    2. Contents: Adv. Mater. 12/2005 (pages 1451–1459)

      Article first published online: 7 JUN 2005 | DOI: 10.1002/adma.200590057

    3. Polymer-Directed Formation of Unusual CaCO3 Pancakes with Controlled Surface Structures (pages 1461–1465)

      S. F. Chen, S. H. Yu, T. X. Wang, J. Jiang, H. Cölfen, B. Hu and B. Yu

      Article first published online: 7 JUN 2005 | DOI: 10.1002/adma.200401957

      Thumbnail image of graphical abstract

      A double hydrophilic block copolymer (DHBC) is used as a crystal-growth modifier for controlled self-assembly of complex and unusual calcite pancakes with multiple stacked and porous layers (see Figure), based on a polymer-directed crystallization mechanism. The results demonstrate that it is possible to manipulate the ability of selective adsorption and stabilization of the DHBCs in order to control the directed crystal growth process.

    4. Electroactive Luminescent Self-Assembled Bio-organic Nanowires: Integration of Semiconducting Oligoelectrolytes within Amyloidogenic Proteins (pages 1466–1471)

      A. Herland, P. Björk, K. P. R. Nilsson, J. D. M. Olsson, P. Åsberg, P. Konradsson, P. Hammarström and O. Inganäs

      Article first published online: 7 JUN 2005 | DOI: 10.1002/adma.200500183

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      Electroactive luminescent bio-organic nanowires, 10 nm in width and with lengths up to 10 μm (see Figure), are generated through co-assembly of protein amyloid fibrils with conjugated oligoelectrolytes. The electro-optical properties of the wires are demonstrated with reversible electrochemical doping-induced fluorescence quenching, providing evidence for both electrical transport and electroactivity.

    5. Phase Separation of Excimer-Forming Fluorescent Dyes and Amorphous Polymers: A Versatile Mechanism for Sensor Applications (pages 1471–1476)

      B. R. Crenshaw and C. Weder

      Article first published online: 7 JUN 2005 | DOI: 10.1002/adma.200401688

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      A temperature-sensing scheme that relies on kinetically trapping molecular mixtures of a sensor molecule and amorphous host materials in a thermodynamically unstable state is introduced. Subjecting the blends to temperatures above their glass transition leads to irreversible changes of their photoluminescence emission spectra due to phase separation and excimer formation, as shown in the Figure for blend films before (left) and after annealing at 150 °C for 42 h (right).

    6. Direct Patterning of Membrane-Derivatized Colloids Using In-Situ UV-Ozone Photolithography (pages 1477–1480)

      C. Yu, A. N. Parikh and J. T. Groves

      Article first published online: 7 JUN 2005 | DOI: 10.1002/adma.200401586

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      A lithographic method of patterning lipid bilayer membranes on the surface of colloidal particles is described. Three-dimensional, micrometer-resolution patterns on the single fluid lipid bilayer membranes supported on silica microspheres have been generated by in-situ UV photolithography (see Figure). This technique is based on the direct photochemical removal of lipids from the colloid surface in an aqueous environment.

    7. Bottom–Up Fabrication of Carbon-Rich Silicon Carbide Nanowires by Manipulation of Nanometer-Sized Ethanol Menisci (pages 1480–1483)

      M. Tello, R. Garcia, J. A. Martín-Gago, N. F. Martínez, M. S. Martín-González, L. Aballe, A. Baranov and L. Gregoratti

      Article first published online: 7 JUN 2005 | DOI: 10.1002/adma.200401466

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      A nanometer-sized ethyl alcohol meniscus induced between a conductive atomic force microscope tip and a silicon surface (see Figure) allows the fabrication of nanodots or nanowires of SiCx at a predetermined position on the substrate. The meniscus size and kinetic parameters control the nanostructure size.

    8. Angle-Dependent Extinction of Anisotropic Silica/Au Core/Shell Colloids Made via Ion Irradiation (pages 1484–1488)

      J. J. Penninkhof, C. Graf, T. van Dillen, A. M. Vredenberg, A. van Blaaderen and A. Polman

      Article first published online: 7 JUN 2005 | DOI: 10.1002/adma.200401742

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      Spherical colloids with silica cores (300–500 nm diameter) and gold shells (20–60 nm thickness) are shown to deform to form oblate ellipsoids under ion-beam irradiation, as shown in the Figure. The deformation, which can be controlled by ion fluence, is attributed to an ion-induced anisotropic deformation in the amorphous silica that is constrained mechanically by the gold shell. The optical extinction of these samples is highly angle-dependent.

      Corrected by:

      Correction: Angle-Dependent Extinction of Anisotropic Silica/Au Core/Shell Colloids Made via Ion Irradiation

      Vol. 18, Issue 21, 2802, Article first published online: 30 OCT 2006

    9. Fabrication Method for Thermoelectric Nanodevices (pages 1488–1492)

      J. R. Lim, J. F. Whitacre, J.-P. Fleurial, C.-K. Huang, M. A. Ryan and N. V. Myung

      Article first published online: 7 JUN 2005 | DOI: 10.1002/adma.200401189

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      Thermoelectric nanowire-based devices are fabricated by the electrodeposition of n-type Bi2Te3 and p-type BiSbTe nanowire bundles within the same alumina nanotemplate (see Figure). The nanowire bundles are approximately 50 μm in diameter and consist of nanowires 200 nm in diameter and 40 μm in length. These nanostructured materials could be used to create higher-efficiency power generation or cooling devices.

    10. Diels–Alder Reactions of Tetraphenylcyclopentadienones in Nanochannels: Fabrication of Nanotubes from Hyperbranched Polyphenylenes (pages 1492–1496)

      L. Zhi, J. Wu, J. Li, M. Stepputat, U. Kolb and K. Müllen

      Article first published online: 7 JUN 2005 | DOI: 10.1002/adma.200500290

      Thumbnail image of graphical abstract

      Hyperbranched polyphenylene nanotubes are fabricated by Diels– Alder reactions of tetraphenylcyclopentadienones in the nanochannels of porous alumina membranes. Nanotubes with different structures and morphologies, and even highly porous carbon nanotubes (see Figure), can be obtained by adjusting the starting materials and the conditions of in-situ polymerization.

    11. Synthesis of a Self-Assembled Hybrid of Ultrananocrystalline Diamond and Carbon Nanotubes (pages 1496–1500)

      X. Xiao, J. W. Elam, S. Trasobares, O. Auciello and J. A. Carlisle

      Article first published online: 4 APR 2005 | DOI: 10.1002/adma.200401581

      Thumbnail image of graphical abstract

      A self-assembled hybrid of ultrananocrystalline diamond (UNCD) and carbon nanotubes (CNTs) is successfully prepared by their simultaneous growth in an argon-rich Ar/CH4 plasma (see Figure and cover). Control of the relative fractions and configurations of UNCD and CNTs in the hybrid material is demonstrated. This new synthesis pathway enables the development of new nanocarbons with unique mechanical, tribological, and electrochemical properties.

    12. WS2 and MoS2 Inorganic Fullerenes—Super Shock Absorbers at Very High Pressures (pages 1500–1503)

      Y. Q. Zhu, T. Sekine, Y. H. Li, W. X. Wang, M. W. Fay, H. Edwards, P. D. Brown, N. Fleischer and R. Tenne

      Article first published online: 7 JUN 2005 | DOI: 10.1002/adma.200401962

      Thumbnail image of graphical abstract

      Superb antishock WS2 inorganic fullerenes (IF) can sustain shock pressures up to 25 GPa, suggesting that these IFs are probably the toughest cage molecules known. The Figure shows images of a) pre- and b) post-shock WS2 IF nanoparticles. These IFs may have great potential to withstand very high applied loads when used as solid-state lubricants.

    13. From Entropic to Enthalpic Elasticity: Novel Thermoplastic Elastomers from Syndiotactic Propylene–Ethylene Copolymers (pages 1503–1507)

      C. De Rosa and F. Auriemma

      Article first published online: 7 JUN 2005 | DOI: 10.1002/adma.200401968

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      Syndiotactic propylene–ethylene copolymers show entropic or enthalpic elasticity depending on ethylene concentration (see Figure). Enthalpic elasticity is due to a reversible transition between transplanar and helical polymorphic forms during stretching, and allows maintenance of elasticity even for highly crystalline materials.

    14. Directed Self-Assembly of Spherical Particles on Patterned Electrodes by an Applied Electric Field (pages 1507–1511)

      A. Winkleman, B. D. Gates, L. S. McCarty and G. M. Whitesides

      Article first published online: 7 JUN 2005 | DOI: 10.1002/adma.200401958

      Thumbnail image of graphical abstract

      Self-assembly of 100 μm spheres on a patterned electrode under the influence of an applied electric field is demonstrated. This process occurs for ordered arrays and arbitrary patterns, over areas up to ∼0.7 cm2, with a defect rate (e.g., missing spheres or extra spheres, circled in Figure) of about 1 %. These arrays of microspheres can be transferred into polymeric matrices, such as poly(dimethylsiloxane), polyurethane, and epoxy.

    15. CdSe-Sensitized p-CuSCN/Nanowire n-ZnO Heterojunctions (pages 1512–1515)

      C. Lévy-Clément, R. Tena-Zaera, M. A. Ryan, A. Katty and G. Hodes

      Article first published online: 7 JUN 2005 | DOI: 10.1002/adma.200401848

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      A fully inorganic analogue of the nanostructured dye-sensitized solar cell is fabricated using an electrochemically grown n-ZnO/CdSe core–shell nanowire array (see Figure). Filling the voids between the nanowires with p-type wide-bandgap CuSCN by a solution-deposition technique leads to an extremely thin solar cell exhibiting 2.3 % energy-conversion efficiency.

    16. Aerogels with a Microporous Crystalline Host Phase (pages 1515–1518)

      C. Daniel, D. Alfano, V. Venditto, S. Cardea, E. Reverchon, D. Larobina, G. Mensitieri and G. Guerra

      Article first published online: 7 JUN 2005 | DOI: 10.1002/adma.200401762

      Thumbnail image of graphical abstract

      High-porosity syndiotactic polystyrene aerogels characterized by nanofibrils that give rise to a microporous crystalline δ-phase (see Figure) present a high sorption capacity for volatile organic compounds at low concentrations, typical of the δ-phase, as well as high sorption kinetics, typical of aerogels. These sorption properties make these new aerogels very promising for industrial applications in chemical separations and water purification.

    17. Single-Crystal SiC Nanowires with a Thin Carbon Coating for Stronger and Tougher Ceramic Composites (pages 1519–1523)

      W. Yang, H. Araki, C. Tang, S. Thaveethavorn, A. Kohyama, H. Suzuki and T. Noda

      Article first published online: 7 JUN 2005 | DOI: 10.1002/adma.200500104

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      SiC nanowires (NWs) reinforce SiC matrix composites with high efficiency. With the incorporation of ∼ 6 vol.-% randomly oriented single-crystal SiC NWs in the matrices, the fracture toughnesses and flexural strengths of the composites doubled. The composites (see Figure) were fabricated in situ by a new process based on chemical vapor infiltration. Reinforcement efficiency of the NW is affected by the amount of C deposited on the NWs as the NW/matrix interfacial layer.

    18. Microcontact Printing as a Versatile Tool for Patterning Organic Field-Effect Transistors (pages 1523–1527)

      R. Parashkov, E. Becker, T. Riedl, H.-H. Johannes and W. Kowalsky

      Article first published online: 7 JUN 2005 | DOI: 10.1002/adma.200401967

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      Patterning of organic field-effect transistors can be easily accomplished by microcontact printing combined with subsequent electroplating and electrode-peeling transfer. The method is based on area-selective electrodeposition and diffusion electropolymerization performed on metallized substrates with a previously patterned self-assembled monolayer, which is used as a template in the subsequent deposition of drain and source contacts (see Figure).

    19. Well-Oriented Silicon Thin Films with High Carrier Mobility on Polycrystalline Substrates (pages 1527–1531)

      A. T. Findikoglu, W. Choi, V. Matias, T. G. Holesinger, Q. X. Jia and D. E. Peterson

      Article first published online: 7 JUN 2005 | DOI: 10.1002/adma.200500040

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      Si thin films, grown using ion-beam-assisted deposition of buffer layers on polycrystalline metal-alloy tapes (see Figure), show out-of-plane and in-plane mosaic spreads of 0.8° and 1.3°, respectively, and a room-temperature Hall mobility of 89 cm2 V–1 s–1 for a doping concentration of 4.4 × 1016 cm–3. These results provide proof-of-concept for a promising materials technology that does not require lattice-matched, single-crystal substrates for deposition of well-oriented, high-carrier-mobility semiconductor thin films.

    20. SiC Nanowires Synthesized from Electrospun Nanofiber Templates (pages 1531–1535)

      H. Ye, N. Titchenal, Y. Gogotsi and F. Ko

      Article first published online: 7 JUN 2005 | DOI: 10.1002/adma.200500094

      Thumbnail image of graphical abstract

      Single-crystalline SiC nanowires (NWs) with a SiO2 coating (see Figure) have been grown using electrospun polyacrylonitrile nanofibers as templates. SiC NWs produced in this process have uniform cross-sections, well-ordered structures, and very low concentrations of stacking faults, and contain no catalyst. Some bent or helical SiC NWs with single-crystalline structures are also observed.

    21. High-Performance Organic Transistors Using Solution-Processed Nanoparticle-Filled High-k Polymer Gate Insulators (pages 1535–1539)

      R. Schroeder, L. A. Majewski and M. Grell

      Article first published online: 7 JUN 2005 | DOI: 10.1002/adma.200401398

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      A polymer matrix filled with nanoparticles, used as the gate material, makes solution-processable, low-voltage, organic transistors possible. The device shown here operates at very low voltages (see Figure). Atomic force microscopy shows a relatively homogeneous film, even with a high filling of nanoparticles.

    22. The Deformation of Single, Nanometer-Sized Metal Crystals in Graphitic Shells (pages 1539–1542)

      J. Li and F. Banhart

      Article first published online: 7 JUN 2005 | DOI: 10.1002/adma.200401917

      Thumbnail image of graphical abstract

      Deformation of single, nanometer-sized metal crystals is monitored in situ by transmission electron microscopy (see Figure). Compressive forces from graphitic shells encapsulating Mo or W crystals lead to slow but considerable deformation. The formation of twins and grain boundaries is observed. Sustained or cyclic deformation leads to re-annealing of defects so that a permanent accumulation of defects in the crystals does not occur.

    23. Patterned Gold-Nanoparticle Monolayers Assembled on the Oxide of Silicon (pages 1542–1545)

      E. W. Foster, G. J. Kearns, S. Goto and J. E. Hutchison

      Article first published online: 7 JUN 2005 | DOI: 10.1002/adma.200401728

      Thumbnail image of graphical abstract

      Patterned monolayers of gold nanoparticles are selectively formed on Hf4+-modified silicon dioxide. The 1.5 nm diameter particles are functionalized with a phosphonic acid ligand shell and assembled from solution on a native oxide surface that has been patterned with Hf4+ ions, as shown in the Figure. This system integrates nanoscale components and lithographic patterning. The technique used is precise and compatible with other lithographic techniques.

    24. Facile Synthesis of a Crystalline, High-Surface-Area SnO2 Aerogel (pages 1546–1548)

      T. F. Baumann, S. O. Kucheyev, A. E. Gash and J. H. Satcher Jr.

      Article first published online: 18 APR 2005 | DOI: 10.1002/adma.200500074

      Thumbnail image of graphical abstract

      Preparation of a low-density, high- surface-area SnO2 aerogel (see Figure inset), comprised of interconnected, randomly oriented crystalline (rutile) SnO2 nanoparticles ∼3–5 nm in size is reported. X-ray absorption near-edge structure spectroscopy at the Sn M4,5 edge reveals that the electronic structure of the SnO2 aerogel is similar to that of tetragonal SnO, rather than SnO2 or β-Sn, with additional Sn-related electronic states close to the conduction band minimum.

    25. Magnetoresistive La0.67Sr0.33MnO3 Nanowires (pages 1548–1553)

      C. Li, B. Lei, Z. Luo, S. Han, Z. Liu, D. Zhang and C. Zhou

      Article first published online: 7 JUN 2005 | DOI: 10.1002/adma.200402000

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      Magnetoresistive La0.67Sr0.33MnO3 nanowires (NWs) have been synthesized using pulsed-laser deposition, with a template of MgO NWs. Transport studies reveal a remarkable metal–insulator transition at 325 K, accompanied by room-temperature colossal magnetoresistance (MR) of ∼ 10 % under a 1 T magnetic field. Shape-induced MR was observed for magnetic fields applied parallel or perpendicular to the NW (see Figure).

    26. Rigiflex Lithography for Nanostructure Transfer (pages 1554–1560)

      D. Suh, S.-J. Choi and H. H. Lee

      Article first published online: 7 JUN 2005 | DOI: 10.1002/adma.200402010

      Thumbnail image of graphical abstract

      Rigiflex lithography combines the mold rigidity of imprint lithography, which permits fine patterning, with the mold flexibility of soft lithography, allowing intimate contact of the mold with the surface substrate over a large area. A UV-curable mold based on poly(urethane acrylate) is prepared as a film on a flexible poly(ethylene terephthalate) support, allowing nanopatterns to be prepared by a bilayer-transfer technique (see Figure).

    27. Conference Calendar Adv. Mater. 12/2005 (pages 1561–1563)

      Article first published online: 7 JUN 2005 | DOI: 10.1002/adma.200590059

    28. Author Index and Subject Index: Adv. Mater. 12/2005 (pages 1564–1565)

      Article first published online: 7 JUN 2005 | DOI: 10.1002/adma.200590060

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