Advanced Functional Materials

Cover image for Vol. 13 Issue 5

May, 2003

Volume 13, Issue 5

Pages 343–418

    1. Quadratic Optical Nonlinearities of N-Methyl and N-Aryl Pyridinium Salts (pages 347–357)

      B.J. Coe, J.A. Harris, I. Asselberghs, K. Wostyn, K. Clays, A. Persoons, B.S. Brunschwig, S.J. Coles, T. Gelbrich, M.E. Light, M.B. Hursthouse and K. Nakatani

      Version of Record online: 30 APR 2003 | DOI: 10.1002/adfm.200300026

      The static first hyperpolarizabilities of dipolar pyridinium chromophores are greatly increased by a combination of N-arylation and conjugation extension, according to Stark spectroscopic and hyper-Rayleigh scattering data. The salt trans-N-phenyl-4-(4-dimethylaminophenyl-4-buta-1,3-dienyl)pyridinium hexafluorophosphate (see Figure) crystallizes noncentrosymmetrically and gives intense second harmonic generation.

    2. A Micellar Route to Ordered Arrays of Magnetic Nanoparticles: From Size-Selected Pure Cobalt Dots to Cobalt–Cobalt Oxide Core–Shell Systems (pages 359–364)

      H.-G. Boyen, G. Kästle, K. Zürn, T. Herzog, F. Weigl, P. Ziemann, O. Mayer, C. Jerome, M. Möller, J.P. Spatz, M.G. Garnier and P. Oelhafen

      Version of Record online: 30 APR 2003 | DOI: 10.1002/adfm.200304319

      Monomicellar arrays of Co-salt-loaded inverse diblock copolymer micelles exhibiting a significant hexagonal order have been prepared on top of various substrates with tailored intermicellar distances and structure heights. Removal of the polymer matrix to obtain arrays of pure Co nanoparticles is achieved by first exposing the micelles to an oxygen plasma, followed by a treatment in a hydrogen plasma. Control of the ferromagnetic–antiferromagnetic properties of the Co/Co oxide core/shell particles is possible by exposing pure Co dots to various oxygen partial pressures for 100 s.

    3. Synthesis, Chemical Modification, and Surface Assembly of Carbon Nanowires (pages 365–370)

      A. Amma, B. Razavi, S.K. St. Angelo, T.S. Mayer and T.E. Mallouk

      Version of Record online: 30 APR 2003 | DOI: 10.1002/adfm.200304232

      Glassy carbon nanowires have been synthesized by replication of the pores of alumina membrane templates. The suspended wires show characteristic mobility behavior on different kinds of surfaces due to repulsive or attractive electrostatic nanowire–surface interactions. These interactions can be used to design traps that confine the wires into trenches on the surface (see Figure).

    4. Photodimerization of Coumarin-Derived Pentacyclo[,9.15,15.17,13]octasiloxane to Fabricate a Three-Dimensional Organic–Inorganic Hybrid Material (pages 371–376)

      M. Fujiwara, K. Shiokawa, N. Kawasaki and Y. Tanaka

      Version of Record online: 30 APR 2003 | DOI: 10.1002/adfm.200304294

      An organic–inorganic hybrid material is prepared from a pentacyclo [,9.15,15.17,13]octasiloxane derivative with 8 coumarin groups on the corners of the pseudo-cubic core. The intermolecular photodimerization of these groups leads to the cross-linking of the monomer units in concentrated solution (see Figure). In dilute solution, an intramolecular reaction occurs, so no polymeric material is formed.

    5. Magnetically Induced Large Mesoporous Single-Domain Monoliths Using a Mineral Liquid Crystal as a Template (pages 377–381)

      F. Camerel, J.-C.P. Gabriel and P. Batail

      Version of Record online: 30 APR 2003 | DOI: 10.1002/adfm.200304274

      The imprinting of the alignment of a ribbon-based nematic mineral liquid-crystalline template at low magnetic fields into birefringent centimeter-scale textured silica-based dual inorganic–inorganic composites and porous materials is reported. These transparent monoliths aligned at the centimeter scale, as shown schematically in the Figure, are potential host materials for chromophores, conducting polymers, or large molecules.

    6. The Preparation and Characterization of Small Mesopores in Siloxane-Based Materials That Use Cyclodextrins as Templates (pages 382–386)

      J.-H. Yim, Y.-Y. Lyu, H.-D. Jeong, S.A. Song, I.-S. Hwang, J. Hyeon-Lee, S.K. Mah, S. Chang, J.-G. Park, Y.F. Hu, J.N. Sun and D.W. Gidley

      Version of Record online: 30 APR 2003 | DOI: 10.1002/adfm.200304287

      Porous thin films, containing very small closed pores (∼ 20 Å—see Figure), with a low dielectric constant and excellent mechanical properties have been prepared using a mixture of cyclic silsesquioxane and cyclodextrin as a new porogen. The dielectric constants and refractive index of the films decrease systematically as the amount of porogen in the coating mixture is increased. The electrical and mechanical properties of such films are promising as interlayer dielectrics.

    7. Polyimide Orientation Layers Prepared from Lyotropic Aromatic Poly(Amic Ethyl Ester)s (pages 387–391)

      C. Neuber, R. Giesa and H.-W. Schmidt

      Version of Record online: 30 APR 2003 | DOI: 10.1002/adfm.200304276

      Liquid-crystalline precursor polymers for polyimides have been oriented by a shearing technique and imidized to produce thin films < 100 nm thick. During imidization the high degree of orientation of the poly(amic ethyl ester) is further enhanced (see Figure: before, and cover: after shearing). The films are bulk and surface-oriented, have a surface profile that is controlled by the processing conditions, and can be used as alignment layers in liquid-crystal cells.

    8. Nanoparticle Arrays on Surfaces Fabricated Using Anodic Alumina Films as Templates (pages 393–397)

      M.S. Sander and L.-S. Tan

      Version of Record online: 30 APR 2003 | DOI: 10.1002/adfm.200304290

      High density arrays of nanoparticles on surfaces have been deposited using a template-based method. Nanoporous alumina templates are created by anodizing aluminum films directly on substrates. Because the templates are in good contact with the underlying surface, nanoparticles can be deposited either by vapor-based or wet chemical methods. For example, an array of electrodeposited gold nanorods on silicon has been produced (see Figure).

    9. Dinuclear Metal–Organic Material for Binary Optical Recording (pages 398–402)

      T.D. Trouts, D.S. Tyson, R. Pohl, D.V. Kozlov, A.G. Waldron and F.N. Castellano

      Version of Record online: 30 APR 2003 | DOI: 10.1002/adfm.200304352

      A new dinuclear RuII complex bridged through a photocleavable dianthryl-containing ligand is reported. The photoluminescence from the dinuclear complex is modulated by UV photolysis, permitting non-destructive readout of binary images recorded on the molecular level in PVA polymer films such as that shown in the Figure (from photolysis of a 0.1 % doped film through a TEM grid). One box is 120 μm across.

    10. Molecular Metals Based on BEDT-TTF Radical Cation Salts with Magnetic Metal Oxalates as Counterions: β″-(BEDT-TTF)4A[M(C2O4)3]·DMF (A = NH4+, K+; M = CrIII, FeIII) (pages 403–411)

      T.G. Prokhorova, S.S. Khasanov, L.V. Zorina, L.I. Buravov, V.A. Tkacheva, A.A. Baskakov, R.B. Morgunov, M. Gener, E. Canadell, R.P. Shibaeva and E.B. Yagubskii

      Version of Record online: 30 APR 2003 | DOI: 10.1002/adfm.200304283

      Four new metallic salts of the organic donor molecule bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) with metal oxalate anions, (BEDT-TTF)4A[M(C2O4)3]·DMF, (DMF = dimethylformamide) have been prepared and characterized (see Figure for a projection of a sample with A = NH4+/K+ (0.75:0.25) and M = CrIII). Their calculated Fermi surfaces suggest an interesting magnetoresistance behavior if disorder does not prevent the observation of Shubnikov–de Haas oscillations.

    11. Laser-Induced Direct Lithography for Patterning of Carbon with sp3 and sp2 Hybridization (pages 412–417)

      D. Zbaida, R. Popovitz-Biro, A. Lachish-Zalait, E. Klein, E. Wachtel, Y. Prior and M. Elbaum

      Version of Record online: 30 APR 2003 | DOI: 10.1002/adfm.200304318

      Direct patterning of carbon with sp3 and sp2 hybridization (see Figure) has been achieved by the application of laser-induced lithography. Analyses show two distinct co-existing phases. The dominant one has mottled morphology and diffraction typical of cubic sp3 diamond. The crystallites range in size from 9 to 30 Å. The other phase consists of ordered arrays of graphene sheets, typical of sp2-bonded carbon.