Advanced Materials

Cover image for Vol. 21 Issue 23

June 19, 2009

Volume 21, Issue 23

Pages 2353–2448

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Review
    6. Frontispiece
    7. Communications
    8. Research News
    9. Index
    1. Silk Fibroin Waveguides: Biocompatible Silk Printed Optical Waveguides (Adv. Mater. 23/2009)

      Sara T. Parker, Peter Domachuk, Jason Amsden, Jason Bressner, Jennifer A. Lewis, David L. Kaplan and Fiorenzo G. Omenetto

      Article first published online: 10 JUN 2009 | DOI: 10.1002/adma.200990086

      Thumbnail image of graphical abstract

      The cover shows an artistic rendition that merges silk and fiber optics. Supercontinuum white light is guided through a glass optical fiber that surrounds and illuminates silkworm cocoons. The silkworm cocoons shown here are used as the starting point of an extraction process to isolate pure silk fibroin protein in an aqueous solution. The silk is then reconstituted in the form of optical waveguides, as described by Fiorenzo Omenetto and co-workers on p. 2411, opening new opportunities to guide light in an entirely organic and biocompatible material.

  2. Inside Front Cover

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Review
    6. Frontispiece
    7. Communications
    8. Research News
    9. Index
    1. Nanowire-Templated Epitaxial Growth: Nanowire-Templated Lateral Epitaxial Growth of Low-Dislocation Density Nonpolar a-Plane GaN on r-Plane Sapphire (Adv. Mater. 23/2009)

      Qiming Li, Yong Lin, J. Randall Creighton, Jeffrey J. Figiel and George T. Wang

      Article first published online: 10 JUN 2009 | DOI: 10.1002/adma.200990087

      Thumbnail image of graphical abstract

      George Wang and co-workers report on p. 2416 that low dislocation density a-plane GaN films can be grown by the coalescence of vertically-aligned, single-crystalline GaN nanowires on lattice-mismatched r-plane sapphire. In this technique, shown by the artists' rendering on the inside cover, the nanowires facilitate dramatic strain relaxation in the suspended GaN film, leading to a large reduction in defects.

  3. Contents

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Review
    6. Frontispiece
    7. Communications
    8. Research News
    9. Index
    1. Contents: (Adv. Mater. 23/2009) (pages 2353–2359)

      Article first published online: 10 JUN 2009 | DOI: 10.1002/adma.200990088

  4. Review

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Review
    6. Frontispiece
    7. Communications
    8. Research News
    9. Index
    1. Bioinspired Design of Dynamic Materials (pages 2361–2374)

      Javeed Shaikh Mohammed and William L. Murphy

      Article first published online: 14 APR 2009 | DOI: 10.1002/adma.200803785

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      Emerging bioinspired approaches for materials design are reviewed, with a particular emphasis on hydrogel networks. The image illustrates three of Nature's molecular mechanisms (noncovalent binding, biocatalysis, and conformational flexibility) that are being used to design bioinspired, dynamic materials.

  5. Frontispiece

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Review
    6. Frontispiece
    7. Communications
    8. Research News
    9. Index
    1. Microelectromechanical Systems: All-Oxide Crystalline Microelectromechanical Systems: Bending the Functionalities of Transition-Metal Oxide Thin Films (Adv. Mater. 23/2009)

      Luca Pellegrino, Michele Biasotti, Emilio Bellingeri, Cristina Bernini, Antonio Sergio Siri and Daniele Marré

      Article first published online: 10 JUN 2009 | DOI: 10.1002/adma.200990089

      Thumbnail image of graphical abstract

      Freestanding structures can be employed to induce strain at their surfaces upon bending. Luca Pellegrino and co-workers show on p. 2377 that a crystalline SrTiO3 (001) thin film cantilevered structure that can be used as a flexible substrate for the epitaxial deposition of correlated oxide films. Surface strain generated by bending is transmitted to the epitaxial (La,Sr)MnO3 film producing a reversible change of its electrical resistance.

  6. Communications

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Review
    6. Frontispiece
    7. Communications
    8. Research News
    9. Index
    1. All-Oxide Crystalline Microelectromechanical Systems: Bending the Functionalities of Transition-Metal Oxide Thin Films (pages 2377–2381)

      Luca Pellegrino, Michele Biasotti, Emilio Bellingeri, Cristina Bernini, Antonio Sergio Siri and Daniele Marré

      Article first published online: 20 APR 2009 | DOI: 10.1002/adma.200803360

      Thumbnail image of graphical abstract

      A crystalline all-oxide microelectromechanical system is presented. A suspended SrTiO3(001) cantilever is employed as flexible substrate for the deposition of epitaxial transition-metal oxide films. A strain generator device for oxide films is thus demonstrated, changing the conductivity of an overgrown epitaxial (La,Sr-)-MnO3 film by bending downward the SrTiO3 element with an AFM tip or a gate voltage bias.

    2. Reversible Hydrogen Storage in Hydrogel Clathrate Hydrates (pages 2382–2386)

      Fabing Su, Christopher L. Bray, Benjamin O. Carter, Gillian Overend, Catherine Cropper, Jonathan A. Iggo, Yaroslav Z. Khimyak, Andrew M. Fogg and Andrew I. Cooper

      Article first published online: 23 MAR 2009 | DOI: 10.1002/adma.200803402

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      The use of inexpensive hydrogels as supports to significantly improve H2 enclathration kinetics and capacities in THF–H2O clathrate hydrate with respect to bulk solutions is demonstrated. Polymer hydrogels give rise to significant rate and capacity enhancements for hydrogen clathrate formation with respect to unmixed bulk systems, suggesting potential for accelerated gas-storage kinetics in clathrate-based technologies.

    3. Structure and Field-Emission Properties of Sub-Micrometer-Sized Tungsten-Whisker Arrays Fabricated by Vapor Deposition (pages 2387–2392)

      Shiliang Wang, Yuehui He, Xiaosheng Fang, Jin Zou, Yong Wang, Han Huang, Pedro M. F. J. Costa, Min Song, Baiyun Huang, Chain T. Liu, Peter K. Liaw, Yoshio Bando and Dmitri Golberg

      Article first published online: 23 MAR 2009 | DOI: 10.1002/adma.200803401

      Thumbnail image of graphical abstract

      Sub-micrometer-sized tungsten-whisker arrays are synthesized by a catalyst- and template-free vapor-deposition process. The resultant whiskers have a hexagonal cross-section, sharp pyramidal tip, and large aspect ratio. The excellent field-emission properties of the whisker arrays, which can be tuned varying the diameters of the synthesized whiskers, are demonstrated.

    4. ZnS/ZnO Heterojunction Nanoribbons (pages 2393–2396)

      Xia Fan, Ming-Liang Zhang, Ismathullakhan Shafiq, Wen-Jun Zhang, Chun-Sing Lee and Shuit-Tong Lee

      Article first published online: 23 MAR 2009 | DOI: 10.1002/adma.200802049

      Thumbnail image of graphical abstract

      Stable ZnS/ZnO heterostructural nanoribbons are obtained via controlling the amount of O2 during growth. The heterojunction is composed of single-crystal side-by-side nanoribbons of ZnS ([0001] direction) and ZnO ([11–2–1] direction). This work demonstrates the possibility of producing high-quality crystalline heterostructures at the nanoscale from two materials with a large lattice mismatch.

    5. Manipulating Charges and Excitons within a Single-Host System to Accomplish Efficiency/CRI/Color-Stability Trade-off for High-Performance OWLEDs (pages 2397–2401)

      Qi Wang, Junqiao Ding, Dongge Ma, Yanxiang Cheng, Lixiang Wang and Fosong Wang

      Article first published online: 23 MAR 2009 | DOI: 10.1002/adma.200803312

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      To reveal superior efficiency/CRI/color-stability trade-off for OWLED fabrications, a single-host concept is proposed in which the primary-color emitters are rationally arranged to render two types (R–G–B and RG–B) of OWLEDs with ultrahigh electroluminescence performance. Comprehensive experimental and theoretical evidence reveal that careful management of charges and excitons is the key to the realization of such high performances.

    6. Temperature- and pH-Sensitive Multicolored Micellar Complexes (pages 2402–2406)

      Yong-Yong Li, Han Cheng, Jing-Ling Zhu, Lin Yuan, Yu Dai, Si-Xue Cheng, Xian-Zheng Zhang and Ren-Xi Zhuo

      Article first published online: 23 MAR 2009 | DOI: 10.1002/adma.200803770

      Thumbnail image of graphical abstract

      Novel multicolored micellar complexes self-assembled from P(NIPAAm-co-EIPPMMA · Eu(DMB)3)-b-PVPhol and P(NIPAAm-co-HEMA · FITC)-b-PVP polymers are prepared. These complexes exhibit temperature- and pH-dependent fluorescence, suggesting promising applications for in vivo sensing of the pH and temperature in complicated microenvironments.

    7. Direct-Write Assembly of 3D Hydrogel Scaffolds for Guided Cell Growth (pages 2407–2410)

      Robert A. Barry III, Robert F. Shepherd, Jennifer N. Hanson, Ralph G. Nuzzo, Pierre Wiltzius and Jennifer A. Lewis

      Article first published online: 26 MAR 2009 | DOI: 10.1002/adma.200803702

      Thumbnail image of graphical abstract

      Planar and 3D hydrogel scaffolds are patterned via direct-write assembly of hydrogel-based inks. Through simultaneous ink writing and UV polymerization, both 1D and 3D microperiodic scaffolds are created. 3T3 murine fibroblasts are seeded onto the scaffolds and their process development is observed using fluorescence microscopy.

    8. Biocompatible Silk Printed Optical Waveguides (pages 2411–2415)

      Sara T. Parker, Peter Domachuk, Jason Amsden, Jason Bressner, Jennifer A. Lewis, David L. Kaplan and Fiorenzo G. Omenetto

      Article first published online: 8 APR 2009 | DOI: 10.1002/adma.200801580

      Thumbnail image of graphical abstract

      Biocompatible silk optical waveguides are fabricated by direct-write assembly and demonstrated to guide light in both straight and curved architectures. These waveguides can easily be doped or functionalized with bioactive molecules, and are promising materials for biophotonic devices.

    9. Nanowire-Templated Lateral Epitaxial Growth of Low-Dislocation Density Nonpolar a-Plane GaN on r-Plane Sapphire (pages 2416–2420)

      Qiming Li, Yong Lin, J. Randall Creighton, Jeffrey J. Figiel and George T. Wang

      Article first published online: 20 APR 2009 | DOI: 10.1002/adma.200802532

      Thumbnail image of graphical abstract

      Coalescence of a vertically aligned GaN nanowire array on r-plane sapphire, a technique called nanowire-templated lateral epitaxial growth, is used to grow low-dislocation density a-plane GaN. The resulting film is connected to the lattice-mismatched substrate by nanowires, which facilitates dramatic strain relaxation and leads to a significant reduction in defects.

    10. A Combined Process of In Situ Functionalization and Microwave Treatment to Achieve Ultrasmall Thermal Expansion of Aligned Carbon Nanotube–Polymer Nanocomposites: Toward Applications as Thermal Interface Materials (pages 2421–2424)

      Wei Lin, Kyoung-Sik Moon and C. P. Wong

      Article first published online: 19 MAR 2009 | DOI: 10.1002/adma.200803548

      Thumbnail image of graphical abstract

      Ultrasmall thermal expansion of aligned carbon nanotube–epoxy composites at temperatures below and above the glass transition is achieved by a novel combined process of in situ functionalization and microwave treatment. Carbon nanotube–polymer interfacial bonding is the key to the reduced thermal expansion, enhanced storage modulus, and improved thermal conductivity.

    11. Fluorene-Based Oligomers for Highly Efficient and Stable Organic Blue-Light-Emitting Diodes (pages 2425–2429)

      Chang-Gua Zhen, Zhi-Kuan Chen, Qin-De Liu, Yan-Feng Dai, Richard Yee Cheong Shin, Soon-Yee Chang and John Kieffer

      Article first published online: 26 MAR 2009 | DOI: 10.1002/adma.200900095

      Thumbnail image of graphical abstract

      Highly efficient and stable blue-light-emitting materials consisting of oligofluorenyl blocks and charge transporting segments are synthesized. The external quantum efficiencies of the solution-processed light-emitting diodes were of up to 6.1% and 8.6% for undoped and doped devices, respectively. The exceedingly high efficiency and excellent stability of these devices suggest that these new developed materials are very promising for deep-blue-light OLEDs.

    12. Broadband Nonlinear Optical Response of Graphene Dispersions (pages 2430–2435)

      Jun Wang, Yenny Hernandez, Mustafa Lotya, Jonathan N. Coleman and Werner J. Blau

      Article first published online: 23 MAR 2009 | DOI: 10.1002/adma.200803616

      Thumbnail image of graphical abstract

      A series of unoxidized and defect-free graphene dispersions with large populations of single and multilayer graphenes is prepared by employing high-yield exfoliation of graphene in the liquid phase. The graphene dispersions exhibit broadband optical limiting at 532 and 1064 nm. Nonlinear scattering, originated from the thermally induced solvent bubbles and microplasmas, is responsible for this nonlinear behavior.

    13. Single-Crystalline V2O5 Ultralong Nanoribbon Waveguides (pages 2436–2440)

      Bin Yan, Lei Liao, Yumeng You, Xiaojing Xu, Zhe Zheng, Zexiang Shen, Jan Ma, Limin Tong and Ting Yu

      Article first published online: 23 MAR 2009 | DOI: 10.1002/adma.200803684

      Thumbnail image of graphical abstract

      High-aspect-ratio V2O5 nanoribbons are synthesized by thermal vapor deposition technique. Our results reveal that the nanoribbons can serve as effective active optical waveguides. In addition, the observation of strong Raman signals collected at the end of the ribbon indicate that the unique nanostructure could play a vital role in Raman amplifers and other nonlinear photonic components.

  7. Research News

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Review
    6. Frontispiece
    7. Communications
    8. Research News
    9. Index
    1. In Pursuit of Zero: Polymer Brushes that Resist the Adsorption of Proteins (pages 2441–2446)

      Angus Hucknall, Srinath Rangarajan and Ashutosh Chilkoti

      Article first published online: 21 APR 2009 | DOI: 10.1002/adma.200900383

      Thumbnail image of graphical abstract

      The development of protein-resistant, “non-fouling”, surfaces, followed by recent research on surface-initiated polymerization to fabricate non-fouling polymer brushes on a surface are presented. We demonstrate how the reduction in background noise afforded by protein-resistant polymer brushes yields protein microarrays with a high signal-to-noise ratio in complex fluids, and consequently provides a limit-of-detection for protein analytes in the low femtomolar range.

  8. Index

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Review
    6. Frontispiece
    7. Communications
    8. Research News
    9. Index
    1. Author Index and Subject Index Adv. Mater. 23/2009 (pages 2447–2448)

      Article first published online: 10 JUN 2009 | DOI: 10.1002/adma.200990090

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