Advanced Materials

Cover image for Advanced Materials

March, 2004

Volume 16, Issue 6

Pages 471–566

    1. Contents: Adv. Mater. 6/2004 (pages 471–476)

      Version of Record online: 22 MAR 2004 | DOI: 10.1002/adma.200490016

    2. High-Conductivity Elastomeric Electronics (Adv. Mater. 2004, 16, 393.) (page 477)

      D. S. Gray, J. Tien and C. S. Chen

      Version of Record online: 22 MAR 2004 | DOI: 10.1002/adma.200490017

    3. Comparison of Electronic Transport Measurements on Organic Molecules (Adv. Mater. 2003, 15, 1883.) (page 477)

      A. Salomon, D. Cahen, S. Lindsay, J. Tomfohr, V.B. Engelkes and C.D. Frisbie

      Version of Record online: 22 MAR 2004 | DOI: 10.1002/adma.200490020

    4. Reflection and Absorption Techniques for Optical Characterization of Chemically Assembled Nanomaterials (pages 479–508)

      D. Roy and J. Fendler

      Version of Record online: 22 MAR 2004 | DOI: 10.1002/adma.200306195

      A unified treatment is presented for a number of optical characterization techniques, including surface plasmon resonance spectroscopies (T-LSPR and P-SPR), infrared reflection absorption spectroscopies (PS-FTIRRAS, PM- FTIRRAS, and SEIRRAS), and infrared ellipsometry. Selected applications of these techniques are illustrated for the characterization of monolayer protected clusters (MPCs), self-assembled monolayers (SAMs), and related nanostructures (see Figure).

    5. Novel Citric Acid-Based Biodegradable Elastomers for Tissue Engineering (pages 511–516)

      J. Yang, A. R. Webb and G. A. Ameer

      Version of Record online: 22 MAR 2004 | DOI: 10.1002/adma.200306264

      The synthesis and characterization of novel biodegradable elastomers, exemplified by poly(1,8-octanediol- co-citric acid), is reported. Biodegradation, mechanical, and biocompatibility data suggest very good potential for use as porous scaffolds in cardiovascular tissue engineering (see Figure). Material properties can be tailored by modulating the monomer ratio and post-polymerization conditions.

    6. A Multidye Nanostructured Material for Optical Data Storage and Security Data Encryption (pages 516–520)

      H. H. Pham, I. Gourevich, J. K. Oh, J. E. N. Jonkman and E. Kumacheva

      Version of Record online: 26 FEB 2004 | DOI: 10.1002/adma.200306156

      A new class of materials for optical data storage and security data encryption is reported. Multidye colloid particles comprising different dyes in different phases are employed as the building blocks to produce a multicolored multiphase polymeric material. The incorporation of dyes in different phases minimizes energy transfer, provides selective dye photobleaching, and allows storage of different data on a single spot (see Figure and also cover).

    7. Multilayer Transfer Printing for Polyelectrolyte Multilayer Patterning: Direct Transfer of Layer-by-Layer Assembled Micropatterned Thin Films (pages 520–525)

      J. Park and P. T. Hammond

      Version of Record online: 18 FEB 2004 | DOI: 10.1002/adma.200306181

      Patterning of polyelectrolyte multilayers by direct transfer of thin films to substrates using positively charged poly(dimethylsiloxane) stamps is demonstrated. Sequentially printed multilayer composites and strong electrostatic interactions between patterns and substrate allow multilevel and multicomponent pattern structures to be achieved (see Figure).

    8. Room-Temperature Nanoimprint Lithography of Non-thermoplastic Organic Films (pages 525–529)

      D. Pisignano, L. Persano, M. F. Raganato, P. Visconti, R. Cingolani, G. Barbarella, L. Favaretto and G. Gigli

      Version of Record online: 22 MAR 2004 | DOI: 10.1002/adma.200305832

      A grating resolution of up to 200 nm is achieved using room-temperature nanoimprint lithography on several different light-emitting low-molar-mass organic semiconductors, without any degradation of the active materials after patterning (see Figure). This could be the only process that permits the transfer of a height profile to films of this very important class of low-molar-mass conjugated molecules with poor thermoplastic behavior.

    9. From Hollow to Dense Spheres: Control of Dipolar Interactions by Tailoring the Architecture in Colloidal Aggregates of Superparamagnetic Iron Oxide Nanocrystals (pages 529–533)

      P. Tartaj, T. González-Carreño and C. J. Serna

      Version of Record online: 22 MAR 2004 | DOI: 10.1002/adma.200305814

      The synthesis of spherical colloidal aggregates (see Figure) of superparamagnetic iron oxide nanocrystals with different packing fractions is reported. Using a mean-field model, the magnitude of dipolar interactions between nanomagnets has been correlated with differences in their assembly. The results could help understanding of the magnetic behavior of magnetic liposomes and hollow capsules, which are promising for drug delivery.

    10. Enhancement in the Orientation of the Microdomain in Block Copolymer Thin Films upon the Addition of Homopolymer (pages 533–536)

      U. Jeong, D. Y. Ryu, D. H. Kho, J. K. Kim, J. T. Goldbach, D. H. Kim and T. P. Russell

      Version of Record online: 22 MAR 2004 | DOI: 10.1002/adma.200306113

      Cylindrical microdomains in thin films of mixtures of polystyrene-block- poly(methyl methacrylate) and poly(methyl methacrylate) (PMMA) homopolymer are oriented normal to the film surface (see Figure). Confining the PMMA homopolymer to the microdomains increases the persistence of microdomain orientation over large distances; thus, aspect ratios up to ∼10 are achievable without the use of an external field.

    11. High-Efficiency, Saturated Red-Phosphorescent Polymer Light-Emitting Diodes Based on Conjugated and Non-Conjugated Polymers Doped with an Ir Complex (pages 537–541)

      C. Jiang, W. Yang, J. Peng, S. Xiao and Y. Cao

      Version of Record online: 22 MAR 2004 | DOI: 10.1002/adma.200306331

      High-efficiency red-emitting polymer light-emitting diodes utilizing [PhqIr]-doped non-conjugated and conjugated polymers (see Figure) in the presence of electron transport molecules are reported. An external quantum efficiency of 12 % photon/electron and a luminous efficiency of 5.2 cd/A with saturated red emission at 624 nm are demonstrated.

    12. Simple Hydrothermal Synthesis of Nanostructured and Nanorod Zn–Al Complex Oxides as Novel Nanocatalysts (pages 541–545)

      S. C. Shen, K. Hidajat, L. E. Yu and S. Kawi

      Version of Record online: 22 MAR 2004 | DOI: 10.1002/adma.200305783

      Nanoparticles of Zn–Al complex oxides (see Figure) have been successfully synthesized in large quantities using a simple hydrothermal process without a surfactant. When these nanomaterials with high surface areas are used as the catalyst for selective reduction of NOx, they show high activity, thermal/hydrothermal stability, and high selectivity to N2. The results indicate good potential for application of these new nanomaterials as environmental catalysts.

    13. Low-Temperature Growth of Well-Aligned β-Ga2O3 Nanowires from a Single-Source Organometallic Precursor (pages 545–549)

      K.-W. Chang and J.-J. Wu

      Version of Record online: 22 MAR 2004 | DOI: 10.1002/adma.200306299

      The growth of well-aligned Ga2O3 nanowires at low temperature (550 °C) is reported (see Figure). A single-source precursor of gallium acetylacetonate is employed as the reactant for the growth of the nanowires by a vapor–liquid–solid route. Structural characterization by X-ray diffraction and transmission electron microscopy reveals that the nanowires are preferentially oriented in the (2?01) direction.

    14. Radial Electromechanical Properties of Carbon Nanotubes (pages 549–552)

      C. Gómez-Navarro, P. J. de Pablo and J. Gómez-Herrero

      Version of Record online: 22 MAR 2004 | DOI: 10.1002/adma.200305678

      The radial electromechanical properties of carbon nanotubes have been measured. The electrical conductance of single-walled carbon nanotubes (SWNTs) as a function of the loading force and bias voltage applied by an atomic force microscope tip is reported (see Figure). An increase of the conductance due to the tip–SWNT electrical contact formation and a drop of the conductance at high loading forces due to radial molecule deformation are observed (see also inside front cover).

    15. New Composite Electrode Architecture and Improved Battery Performance from the Smart Use of Polymers and Their Properties (pages 553–557)

      D. Guy, B. Lestriez and D. Guyomard

      Version of Record online: 22 MAR 2004 | DOI: 10.1002/adma.200306075

      The smart use of polymers and their properties can be exploited to give new composite electrode architectures (see Figure) and improved battery performance. A new polymeric binder combination with controlled polymer-filler (carbon black) interactions is described. Composite electrodes based on this binder and Li1.1V3O8 display capacities that are up to twice as high as those obtained for a standard lithium battery electrode.

    16. Solution-Processable Red Phosphorescent Dendrimers for Light-Emitting Device Applications (pages 557–560)

      T. D. Anthopoulos, M. J. Frampton, E. B. Namdas, P. L. Burn and I. D. W. Samuel

      Version of Record online: 22 MAR 2004 | DOI: 10.1002/adma.200306095

      High efficiency, solution-processed electroluminescent devices are realized using two new red-light-emitting phosphorescent dendrimers (see Figure). By modulating the dendrimer architecture (changing the structure of the luminescent core), tuning of the emission spectra is demonstrated. Processability in organic solvents is achieved by incorporating the red-emitting cores into dendrimers with suitable surface groups and dendrons.

    17. Three-Dimensional Assembly of Polymer Microstructures at Low Temperatures (pages 560–564)

      Y. Yang, C. Zeng and L. J. Lee

      Version of Record online: 22 MAR 2004 | DOI: 10.1002/adma.200306159

      A low-temperature, low-pressure polymer bonding technique for three-dimensional assembly of microstructures (see Figure; scale bar 5 μm) based on carbon dioxide (CO2)-enhanced chain entanglement near the polymer surfaces is presented. The environmentally benign utilization of supercritical CO2 offers scope for the production of polymer-based biomedical applications and devices.