Advanced Materials

Cover image for Advanced Materials

February 1995

Volume 7, Issue 2

Pages fmi–fmi, 109–250

  1. Masthead

    1. Top of page
    2. Masthead
    3. Essay
    4. Articles
    5. Communications
    6. Research News
    7. Book Reviews
    1. Masthead (page fmi)

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070201

  2. Essay

    1. Top of page
    2. Masthead
    3. Essay
    4. Articles
    5. Communications
    6. Research News
    7. Book Reviews
    1. Materials Science in Spain (pages 109–110)

      Prof. Domingo González

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070202

      Materials Science in Spain is the topic of this special issue. Here, the importance of advaned and new materials to the economic growth of a country are examined, the structure, funding, and general aims of basic and applied Spanish materials science presented, and the topics covered in the rest of the special issue introduced.

  3. Articles

    1. Top of page
    2. Masthead
    3. Essay
    4. Articles
    5. Communications
    6. Research News
    7. Book Reviews
    1. CVD of Covalent Compounds and high-Tc superconductors (pages 111–119)

      Dr. Cristina Gómez-Aleixandre, Dr. Olga Sanchez, Prof. José M. Albella, Dr. José Santiso and Dr. Albert Figueras

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070203

      Chemical vapor deposition at high temperatures provided the deposited atoms with the necessary surface mobility to ensure crystallinity and epitaxial growth. The use of high-temperaure CVD in the deposition of high-Tc superconducting ceramics and covalent materials such as diamond (see Figure) and boron nitride is reviewed, and, for example, the methods used to maintain the terahedral arrangement of neighboring atoms during deposition discussed.

    2. Sol–gel processing of optical and electrooptical materials (pages 120–129)

      Dr. David Levy and Dr. Luis Esquivias

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070204

      The sol–gel process represents a room-temperature method of producing a wide range of ceramic materials through the formation of a glassy network by the polymerization of suitable monomers. The use of the technique to produce, for example, sonogels, organic-inorganic composites, NLO glasses, and electrooptical materials such as gel-glass dispersed liquid crystald (GDLCs) is reviewed. An example of a GDLC is shown on this issue's front cover, 4-pentyl-4-biphenylcarbonitrile in the LC state being dispersed in a thin film of silica.

    3. Mechanical properties of Ultrahigh Boron Steels (pages 130–136)

      Dr. José A. Jiménez, Dr. Gaspar González-Doncel and Prof. Oscar A. Ruano

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070205

      A fine and stable grain size in steel results in greatly improved mechanical properties. In analogy to the addition of larger quantities of carbon to form ultra-high carbon steels, the formation of borides in steel through rapid solidification and powder metallurgical techniques leads to the required grain size (see Figure) The materials processing, microstructure control, and properties of the materials are reviewed.

    4. Zeolites and Zeotypes as catalysts (pages 137–144)

      Prof. Avelino Corma and Dr. Agustin Martinez

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070206

      Microreactors based on zeolites and related materials are one of the latest developments in the field which started with the use of crystalline aluminosilicates for catalysis in the 1960s. These crystalline materials are highly thermally and hydrothermally stable, the number and strength of their acid sites can be conrolled, they have a high adsorption capacity, and contain channels of molecular dimensions, properties of interest for a number of applications. The history of the field is traced and a number of new applications of these materials is reviewed.

  4. Communications

    1. Top of page
    2. Masthead
    3. Essay
    4. Articles
    5. Communications
    6. Research News
    7. Book Reviews
    1. Synthesis of regioregular poly(methyl pyridinium vinylene): An isoelectronic analogue to poly(phenylene vinylene) (pages 145–147)

      Michael J. Marsella, Dr. Dian-Kui Fu and Prof. Timothy M. Swager

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070207

      Poly(phenylene vinylene), PPV, and its derivatives have generated much interest due to their high conductivity and electroluminescent properties which allow for LED applications. Highly electron-deficient PPV analogues are desirable as they would allow the use of environmentally stable metals as the electrodes in the LEDs. The title compound (see Figure) is just such as material.

    2. Thermally stable polymers: Novel aromatic polyamides (pages 148–151)

      Dr. Juvier de Ahajo, Dr. José G. de la Campa, Dr. Angel E. Lozano and Dr. Julio C. Alvarez

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070208

      The solubility, processability, thermal behavior, and even the hydrophilicity of thermally stable aromatic polyamides can be influenced profoundly and relatively easily and inexpensively, by the introduction of bulky pendant groups. Here, the influence of various pendant groups anchored in the 5-position of the isophthaloyl moiety of polyisophthalomides is assesed.

    3. Extraction of aqueous gold sols with styrene/2-vinylpyridine block copolymers in toluene (pages 151–154)

      G. Arno Roescher and Prof. Martin Möller

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070209

      Polymers containing small noble-metal particles are of interest for catalysis and in the generation of optically tunable composites. The currently used process results in materials which are often difficult to process. A method is presented here for the direct transfer of small gold particles from an aqueous sol into a non-aqueous polymer solution (e.g. a block copolymer, see Figure) facilitating the formation of films.

    4. New polymer electrolyte nanocomposites: Melt intercalation of poly(ethylene oxide) in mica-type silicates (pages 154–156)

      Dr. Richard A. Vaia, Dr. S. Vasudevan, Dr. Wlodzimierz Krawiec, Dr. Lawrence G. Scanlon and Prof. Emmanual P. Giannelis

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070210

      The electrochemical performance of polymer-based batteries can be improved by the addition of inorganic fillers to the polymer electrolyte, giving composite polymer electrolytes. The use of polymer nanocomposites, where the dimensions of the filler particles are reduced, should lead to the improvement of the performance of the electrolytes. Here, the direct intercalation of poly(ethylene oxide) into Na⊕ and Li⊕-exchanged layered silicates and the properties of the resulting nanocomposites is reported.

    5. Immobilization of functionalized lipids in a random poly(methacrylate) copolymer monolayer (pages 156–160)

      Klaus Lowack and Dr. Christiane A. Helm

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070211

      Model membranes, based on thin organic films containing an even, random distribution of functionalized amphiphilic lipid molecules, are reported. The monolayers are stabilized by polymerization and can be transferred to solid substrates using he Langmuir–lodgett technique, allowing structures such as that shown in the Figure to be produced.

    6. On the nature of methyltrioxorhenium(VII) encapsulated in zeolite Y (pages 160–163)

      Dr. Andrzej Malek and Prof. Geoffrey Ozin

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070212

      Zeolite-encapsulated molecular forms of rhenium oxide offer the opportunity to tune the physico-chemical properties of the materials due to the wide range of oxidation states available to rhenium (+7–1) This can lead to nanomaterials with interesting electronic, optical, and catalytic properties. Here, the encapslation, structural characterization, thermal and chemical stability of CH3ReO3 in both sodium and acid forms of zeolite Y are reported.

    7. In situ X-ray diffraction evidence of guest molecule reorientation during an intercalation reaction (pages 163–166)

      Dr. John S. O. Evans, Stephen Barlow, Dr. Heng-Vee Wong and Dr. Dermot O'Hare

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070213

      Superconductivity and co-operative magnetism are just two of the interesting features of materials based on the intercalation of organic or organometallic moieties into lamellar host lattices. In situ energ dispersive X-ray diffraction is used here to probe the kinetic and mechanistic details of guest reorientation during intercalation (see Figure).

    8. Nanoporous tin(IV) sulfides: Thermochemical properties (pages 166–170)

      Tong Jiang, Prof. Geoffrey A. Ozin and Dr. Robert L. Bedard

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070214

      The porosity, the integrity of the framework and any envisaged applications of sulfide-based nanoporous layered materials produced using organic templates, depend upon the stability of the materials with respect to the thermally induced template removal process. Here, the thermochemical properties of two such materials are examined using a variety of techniques and conclusions drawn concerning the thermal stability range and the reconstructio processes which take place.

    9. Second harmonic generation in ferroelectric liquid crystalline thiadiazole derivatives (pages 170–173)

      Martina Loos-Wildenauer, Stefan Kunz, Dr. Ingrid G. Voigt-Martin, Dr. Alexander Yakimanski, Dr. Erik Wischerhoff, Prof. Rudolf Zentel, Prof. Carsten Tschierske and Meike Müller

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070215

      Ferroelectric liquid crystals are of interest for applications in second order nonlinear optical experiments as they combine a thermodynamically stable polar structure with mobility. Low-molecular weight-(see Figure) and siloxane-fixed FLCs are reportd which contain a donor-acceptor π system in a heterocylic ring whic does not disturb the desired rod-like shape of the molecules.

    10. Paramagnetic nematic liquid crystals with an iron core (pages 173–176)

      Dr. Mercedes Marcos, Dr. José Luis Serrano, Dr. Pablo J Alonso and Dr. Jesús I. Martínez

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070216

      Metal-containing liquid crystals are of great current interest due to their interesting electrooptic and magnetic properties. Paramagnetic liqid crystals, whose director can be oriented parallel or perpendicular to a magnetic field are particularly interesting and examples have been synthesized containing copperand vanadium. Here, examples of these materials containing iron(III) are reported, and are found to exhibit a paramagnetic nematic mesophaseand, in some cases, a smectic C phase as well.

    11. Microwave-assisted synthesis of aluminum nitride (pages 177–179)

      Dr. Peelamedu D. Ramesh and Prof. Kalva J. Rao

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070217

      Aluminum nitride is an important ad high-cost ceramic materials used in the electronics industry due to its combination of thermal conductivity, high strength; low thermal expansivity, and low dielectric constant. A new, simple and attractive route to sbmicrometer AlN powder (see Figure) is reported based on the use of microwave radiation.

  5. Research News

    1. Top of page
    2. Masthead
    3. Essay
    4. Articles
    5. Communications
    6. Research News
    7. Book Reviews
    1. Nanocomposite materials with controlled ion mobilityk (pages 180–184)

      Prof. Eduardo Ruiz-Hitzky, Dr. Pilar Aranda, Dr. Blanca Casal and Dr. Juan C. Galván

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070218

      The intercalation or entrapment of oxyethylene compounds, crown ethers, and poly(ethylene oxide) into inorganic osts provides the opportnity to design and prepare nanocomposite maerials useful for membrane and solid electrolyte applications. Crown ethers incorporated into the membranes produced by intercalation can act as ion-selective sensors. The field is reviewed and several recently developed applications described.

    2. Layered ceramics (pages 185–189)

      Prof. José S. Moya

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070219

      Layered ceramic-ceramic composites exhibit improved mechancial performance over monolithic composites, design flexibility for the solution of complex technological problems such as with functionally gradient materials (e.g. Al2O3/Y-TZP, see Figure), and provide a model for the sudy of interfacial reactions between two incompatible particulate systems.

    3. Optical properties of Pr3⊕ ions in fluoride glasses (pages 190–193)

      Dr. Rafael Alcalá and Dr. Rafael Cases

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070220

      Materials for near-infrared optical fiber amplifiers are currently receiving considerable attention, and the spectroscopic properties of rare-earth ions in heavy metal fluoride glasses make them prime candidates for amplifiers in the second transmission window of silica fibers (at 1300 nm). The background to this technology is presented and requirements for future improvements discussed.

    4. Three-dimensional woven glass fabrics (pages 194–197)

      Dr. Juan J. Alba and Dr. Antonio Miravete

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070221

      Textile composites are a class of materials in which reinforcement is provided by textile performs. Owing to their unique combination of light weight, flexibility, strength, and toughness these materials have been used in reinforcement in both structural and other applications. New applications i advanced structural composites using 3-D braiding (see Figure) are reviewed.

    5. Polymeric solid-state dye lasers (pages 198–202)

      Dr. Roberto Sastre and Dr. Angel Costela

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070222

      Solid matrices containing laser dyes have been used to produce practical tunable solid state dye lasers with advantages such as compactness, manageability, lack of toxicity and flammablity etc. Polymer matrices have suffered in the past from limited photostability. Recently, polymeric materials with a laser-damage threshold comparable to that of inorganic glasses and crystals have renewed activity in the field. Progress is reviewed.

    6. Polymeric drug delivery systems (pages 203–208)

      Prof. Julio San Román, Dr. Alberto Gallardo and Dr. Belén Levenfeld

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070223

      Controlled drug release- and targeted drug delivery systems based on polymers are reviewed. The design of polymer-drug systems, for example the one shown in the Figure, which contains a solubilizer, the drug linked to the backbone through a spacer, and a targeting moiety for guiding the drug to the desired site, and the factors which influence their effectiveness are discussed.

    7. Synthesis of SiC and Si3N4: An overview (pages 209–211)

      Prof. Francisco Rodríguez-Reinoso and Dr. Javier Narciso

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070224

      Silicon-based structural ceramics, such as silicon carbide, silicon nitride and SiAlON exhibit an attractive range of properties, i.e. high strength, stiffness, and good wear and corrosion resistance, and are considered very appropriate materials for high-temperature applications. Recent progress in the synthesis of oth powder and whiskers of these materials is reviewed.

    8. Uniform colloidal particles in solution: Formation mechanisms (pages 212–216)

      Dr. Manuel Ocaña, Prof. Rafael Rodriguez-Clemente and Prof. Carlos J. Serna

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070225

      Monodisperse colloids have found a wide range of technolgoical applications, in fields as diverse as ceramics, pigments, and catalysis. Recent work in analyzing the mechanism of formation of the particles is reviewed, and the facotrs influencing the size and shape of the colloids, such as the SiO2 particles shown in the Figure, are discussed.

    9. Advanced multiphase magnetic systems (pages 217–220)

      Dr. Manuel Vázquez and Dr. Antonio Hernando

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070226

      The co-existence of different magnetic phases, (i.e. ferromagnetic, antiferromagnetic, paramagnetic) mixed on a nanostructure scale has a profound influence on the soft/hard magnetic behavior of the materials. The effects of thermal treatment of these multiphase systems has been examined and a strong interdependence found between the nanosructure and the exchange correlatio length.

    10. Ferromagnetic interactions in organic/molecular materials (pages 221–225)

      Dr. Jaume Veciana, Joan Cirujeda, Dr. Concepció Rovira and Dr. José Vidal-Gancedo

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070227

      Hydrogen bonding has been used as a crystalline design element in the synthesis of new organic molecular-based magnets. The H bonding controls not only the crystal packing of the organic open-shell molecualr solids ut also generates ferromagnetic interactions and propagates them along predetermined spatial directions. The background of molecular magnetism and the details of this new strategy are discussed.

    11. Electroluminescent porous silicon (pages 226–228)

      Prof. José M. Martínez-Duart, Dr. Vitaly P. Parkhutik, Dr. Ricardo Guerrero-Lemus and Dr. José D. Moreno

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070228

      Porous silicon layers with controlled structure and well-defined surface chemical compositio and the deposition of solid contacts to form electroluminescent devices have recently been reported. The growth and characterization of the layers, several models of the morphology, and the formation processes are discussed, and the use of electrically conductive polymers as the contact materials to porous silicon layers presented.

    12. High temperature superconducting materials (pages 229–232)

      Dr. Miguel Angel Alario-Franco

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070229

      The perovskite structure (see Figure) is the basis of all known high-temperature superconducting materials. Many of the most successful (ighest Tc) materials are based on mercury and thallium phases but, due to the high toxicity of the component compoudns effort has been invested in the substitution of these elements with silver. Progress is reviewed.

    13. C[BOND]H…S and S…S: Two major forces in organic conductors (pages 233–237)

      Dr. Juan J. Novoa, M. Carme Rovira, Dr. Concepció Rovira, Dr. Jaume Veciana and Judit Tarrés

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070230

      The packing in molecular crystals is determined by intermolecular interactions. An understanding of these interactions would enable the design of systems exhibiting effective conductivity and superconductivity. By careful analysis of the shortest intermolecular interactions in the crystal combined with accurate ab-initio calculatins it has been shown that C[BOND]H…X and S…S are the two interactions most likely to influence the structures of these materials.

    14. Silver-selective electrodes based on supported liquid membranes (pages 238–243)

      Prof. Jaume Casabó, Francesç Teixidor, Dr. Luis Escriche, Clara Viñas and Dr. Consuelo Pérez-Jiménez

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19950070231

      Transport-assisted membranes are materials that can perform specific chemical separation and chemical determination tasks. These membranes are conventional polymeric or ceramic membranes incorporating a carrier. The use of this technology in the development of ion-selective electrodes using a variety of cyclic ethers and thioethers (e.g. see Figure) is reviewed.

  6. Book Reviews

    1. Top of page
    2. Masthead
    3. Essay
    4. Articles
    5. Communications
    6. Research News
    7. Book Reviews