Advanced Functional Materials

Cover image for Vol. 12 Issue 6‐7

June, 2002

Volume 12, Issue 6-7

Pages 399–469

    1. Contents: Adv. Funct. Mater. 6+7/2002 (pages 399–401)

      Version of Record online: 17 JUN 2002 | DOI: 10.1002/1616-3028(20020618)12:6/7<399::AID-ADFM399>3.0.CO;2-R

    2. Capillary Force Lithography: Large-Area Patterning, Self-Organization, and Anisotropic Dewetting (pages 405–413)

      K.Y. Suh and H.H. Lee

      Version of Record online: 17 JUN 2002 | DOI: 10.1002/1616-3028(20020618)12:6/7<405::AID-ADFM405>3.0.CO;2-1

      Capillary force lithography, a technique for general purpose patterning on a large area, has been used to obtain various useful microstructures (see Figure) through self-organization. A polydimethylsiloxane mold is placed on a polymer film, which is then heated above its glass-transition temperature. The phenomenon of dewetting in capillary force lithography is also described as a new pathway for realizing anisotropic thin films.

    3. Covalent Attachment of RuII Phenanthroline Complexes to Polythionylphosphazenes: The Development and Evaluation of Single-Component Polymeric Oxygen Sensors (pages 415–419)

      Z. Wang, A.R. McWilliams, C.E.B. Evans, X. Lu, S. Chung, M.A. Winnik and I. Manners

      Version of Record online: 17 JUN 2002 | DOI: 10.1002/1616-3028(20020618)12:6/7<415::AID-ADFM415>3.0.CO;2-Y

      Phosphorescent materials that exhibit efficient quenching by oxygen are of interest for a range of sensing applications, including the visualization of pressure distributions arising from airflow over aircraft (see Figure). A new, single-component processable side-chain RuII phenanthroline inorganic polymer that exhibits excellent sensing characteristics is reported.

    4. Nanostructured Conjugated Polymer Films by Electrophoretic Deposition (pages 420–424)

      K. Tada and M. Onoda

      Version of Record online: 17 JUN 2002 | DOI: 10.1002/1616-3028(20020618)12:6/7<420::AID-ADFM420>3.0.CO;2-D

      Nanostructured thin films of soluble conjugated polymers can be obtained by electrophoretic deposition from colloidal polymer solutions (see Figure), as demonstrated for poly(3-octadecylthiophene). The films are aggregates of 0.1 μm particles, reflecting the colloidal nature of the parent solution; their large surfaces make them promising materials for electrochemical or optoelectronic device applications.

    5. Opal Circuits of Light—Planarized Microphotonic Crystal Chips (pages 425–431)

      S.M. Yang, H. Míguez and G.A. Ozin

      Version of Record online: 17 JUN 2002 | DOI: 10.1002/1616-3028(20020618)12:6/7<425::AID-ADFM425>3.0.CO;2-U

      Planarized opal-based microphotonic crystal chips have been fabricated by directed evaporation-induced self-assembly of microspheres within geometrically defined surface relief patterns. Using this technique it is possible to control the opal crystal shape, size, and orientation, as well as the crystal’s optical properties and functionality. The Figure shows the Bragg diffraction of an opal crystal confined inside a microchannel (see also cover).

    6. Electroless Metallization of Dendrimer-Coated Micropatterns (pages 432–436)

      A.M. Bittner, X.C. Wu and K. Kern

      Version of Record online: 17 JUN 2002 | DOI: 10.1002/1616-3028(20020618)12:6/7<432::AID-ADFM432>3.0.CO;2-1

      Patterned electroless deposition of metals has been achieved by a method involving microcontact printing, chemical surface modification, binding of metal ions, and reduction. Complexation of self-assembled polyamine–amide dendrimers with Pd2+ ions followed by reductive Pd cluster formation creates nuclei for metal deposition. The Figure shows a Cu pattern (black) on an Au substrate; the gray areas were passivated with alkanethiols.

    7. Strain Response from Polypyrrole Actuators under Load (pages 437–440)

      G.M. Spinks, L. Liu, G.G. Wallace and D. Zhou

      Version of Record online: 17 JUN 2002 | DOI: 10.1002/1616-3028(20020618)12:6/7<437::AID-ADFM437>3.0.CO;2-I

      What strain is generated by polymeric low-voltage electromechanical actuators under the influence of an external force? This key feature is investigated by applying increasing external load to polypyrrole films. The actuator response is found to decrease linearly with increasing load, and further depends upon the difference in elastic modulus as the polymer is oxidized or reduced to various extents; the overall performance reflects a balance between these two parameters. These materials are promising replacements for the high-voltage/low-strain piezoelectric actuators currently in use.

    8. Orientation and In-Situ Photopolymerization of a Diacetylene Monomer in Gel-Processed Ultra-High Molecular Weight Polyethylene: Films with Several Optical Security Features (pages 441–446)

      J.S. Uhm, R. Giesa and H.-W. Schmidt

      Version of Record online: 17 JUN 2002 | DOI: 10.1002/1616-3028(20020618)12:6/7<441::AID-ADFM441>3.0.CO;2-1

      Useful optical security features such as photopatterning (see Figure), easily detectable optical anisotropy, and irreversible color change are displayed by the polymer films presented here, i.e., oriented polydiacetylene incorporated in a polyethylene matrix. The optical anisotropy of these films—prepared via gel processing and subsequent tensile drawing—is demonstrated to be dependent on the draw ratio and concentration and form of polydiacetylene in the matrix.

    9. Effect of Chain Rigidity and Effective Conjugation Length on the Structural and Photophysical Properties of Pyridine-Based Luminescent Polymers (pages 447–454)

      M. Tammer, L. Horsburgh, A.P. Monkman, W. Brown and H.D. Burrows

      Version of Record online: 17 JUN 2002 | DOI: 10.1002/1616-3028(20020618)12:6/7<447::AID-ADFM447>3.0.CO;2-E

      Control over the photophysical properties of pyridine-based copolymers (see Figure) is demonstrated. These properties are also related to the chain rigidity and effective conjugation length of each copolymer as determined by light scattering, ellipsometric, and optical measurements. Very different electronic properties are observed for these polymers in the solid state compared to in solution.

    10. Controlled Molecular Alignment in Phthalocyanine Thin Films on Stepped Sapphire Surfaces (pages 455–460)

      J.O. Ossó, F. Schreiber, V. Kruppa, H. Dosch, M. Garriga, M.I. Alonso and F. Cerdeira

      Version of Record online: 17 JUN 2002 | DOI: 10.1002/1616-3028(20020618)12:6/7<455::AID-ADFM455>3.0.CO;2-I

      Step edges along the c-axis of sapphire act as templates for thin films of perfluorinated copper phthalocyanine (F16CuPc) with very good out-of-plane order; the Figure shows AFM images of Al2O3 before (left) and after (right) F16CuPc growth. Under controlled conditions, the effect persists beyond the first few layers, and no azimuthal domains are observed. The high order in these films makes them interesting materials for charge transport devices.

    11. Topological Coding: Towards New Materials for Molecular Electronics (pages 461–469)

      V.A. Karasev, V.V. Luchinin and V.E. Stefanov

      Version of Record online: 17 JUN 2002 | DOI: 10.1002/1616-3028(20020618)12:6/7<461::AID-ADFM461>3.0.CO;2-U

      A model of topological coding of chain polymers is proposed, based on the ability of the polymer main chain to form a helix due to conjugated ionic-hydrogen-bond systems. The model includes the topological code, the algorithm of coding, and the system of physical operators for reconstruction of the encoded structure. From the viewpoint of the model, only proteins, nucleic acids, and their close analogs are recognized as prospective materials of future devices for molecular electronics.