bluuebunny/crossref_metadata_2025 huggingface dataset:
Biomaterials highlights III bone replacements: Implant materials and the modes of implant fixation
Authors: Heimke Günther
Published: May 2005

Biomaterials Highlights III. In the third article of the series, the methods which are used to fix implants to the body's tissue are examined, which include cementing and mechanical fixation. The surfaces of the implants play an important role in interactions with the body. Various coatings are described and the application of isoelastic implants discussed.

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Graphite intercalation compounds, in Berlin
Authors: Setton Ralph
Published: May 2005

Ralph Setton reports on his visit to an international symposium on graphite intercalation compounds, Hermann Schmalzried on the Annual Meeting of the German physical chemists which this year concentrated on solid state chemistry and physics, and Hans Reuter on a meeting on the sol–gel processing of ceramics.
High‐performance Silicon Nitride Materials
Authors: Boberski Cornelia , Hamminger Rainer , Peuckert P. , Aldinger Fritz , Dillinger Reinhard , Heinrich Jürgen , Huber Jürgen
Published: May 2005

The past decade has seen greatly increased interest in ceramic materials with special combinations of properties. Their hardness, high resistance to abrasive and erosive wear, and their good corrosion resistance when used under extreme mechanical and thermal conditions have made ceramics increasingly attractive for applications in mechanical and apparatus engineering. Silicon nitride (Si3N4) in particular, is suitable for the development of a high‐performance, high‐temperature material for vehicle engine construction. Although the properties of Si3N4 materials have been consistently improved in the last few years, they are still not adequate to allow these materials to be used in series production parts, for example as valves in automotive engines. One of the main reasons for this is the wide scatter and low reproducibility of the property parameters, which means that component reliability does not yet meet market requirements. Hence, one aim of Si3N4 materials development is to reduce the structural flaws resulting from physical and chemical inhomogeneity. This objective can only be achieved through a fundamental understanding of all the processing steps, from powder production to the final processing of the components.
Surface analysis I. Imaging surfaces, electric charges and magnetic domains with the atomic force microscope
Authors: Rabe Jürgen P.
Published: May 2005

Surface Analysis I. Atomic Force Microscopy (AFM) provides a method of imaging surfaces on an atomic scale. Closely related to STM, AFM can, however, image insulating materials such as organic molecules. The technique is described and some recent applications discussed in the first article of a regular series from Jürgen Rube on surface analysis techniques.
Preparation‐dependent rectification behavior of lead sulfide particulate films
Authors: Zhao Xiao Kang , McCormick Larry D. , Fendler Janos H.
Published: May 2005

Semiconductor particulate films, exhibiting either p‐type or n‐type behavior, have been produced by varying the synthetic method. Infusion of NH3 into arachidic acid (AA) monolayers floating on an aqueous solution of Pb(NO3)2 and CS(NH 2)2 results in p‐type films while the infusion of H2S into AA monolayers on aqqueous Pb(NO3)2 results in n‐type films. The preparation and characterization of the films are described.
Porous silicon: Quantum sponge structures grown via a self‐adjusting etching process
Authors: Lehmann Volker , Gösele Ulrich
Published: May 2005

Electroluminescence in porous silicon at room temperature has recently been achieved. This is a crucial step in the realization of silicon‐based optoelecctronic devices but there is still work to be done, for example in improving the stability of the electroluminscence. The materials, the effect, and the potential of the materials in the study of quantum confinement effects in silicon sspongess (see figure) are discussed.

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Conductive polymeric Cu(II) tetrakis(3‐methoxy‐4‐hydroxyphenyl) porphyrin as a photosensitizer in a photoelectrochemical Cell
Authors: Malinski Tadeusz , Ciszewski Aleksander , Fish Judith , Kubaszewski Eugeniusz , Czuchajowski Leszek
Published: May 2005

Light‐stimulated electrode processes at semiconductors in contact with electrolytes are attracting attention as they offer a potentially efficient means of converting light into electrical or chemical energy. The title compound, which is an organic p‐type semiconductor, has a small band gap and exhibits high durabiity making it an interesting new cathode material for solar‐driven electrolysis.
Glass‐ceramics in biomedical applications
Authors: Partridge Graham
Published: May 2005

Inorganic Materials VI Glass ceramics play a crucial role in many surgical procedures ranging from hip replacement to dentistry. The surface morhology, chemical composition, and the structural properties of the materials are of utmost importance when deciding the suitability of the materials for particular applications. The various factors involved are discussed.
The european polymer federation
Authors: Spiess Hans W.
Published: May 2005

Coordination of the activities of Europe's polymer scientists is one of the major aims of the European Polymer Federation (EPF). Two‐year presidencies are served by representatives of the various national organizations (currently Germany and from next year Switzerland), workshops and symposia being organized aimed at encouraging the international transfer of reserach expertise. The President of the EPF outlines its activities.
A novel tool for Surface Electronic Structure Calculations—insight into surface self‐diffusion on metals
Authors: Feibehnan Peter J.
Published: May 2005

The diffusion of adatom clusters on surfaces and the nature and energetics of diffusion across a step are crucial in the synthesis of tailored materials, for example growing a structure involving atom A on substrate B. A recently developed method enables the study of such diffusion including concerted substitution diffusion, the mode in which atom A dives into the surface replacing atom B (see figure). The various aspects of the new method are presented.

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ESR studies of fluorinated fullerenes: Evidence for the formation of odd C60Fn species
Authors: Belaish Igal , Davidov Dan , Selig Heny , Fischer John E.
Published: May 2005

Paramagnetic odd‐fluorinated fullerenes have been observed and characterized by electron spin resonance (ESR), revealing evidence that the fluorination process is inhomogeneous and that these species are not very stable. It is suggested, therefore, that the only method of stabilizing odd fluorinated fullerenes would be to capture the fluorine inside the C60 cage. The relative stability of the various fluorinated fullerenes is discussed.
Donor–acceptor substituted polyenes: Orientation in mono‐ and multilayers
Authors: Effenberger Franz , Niesert Claus‐Peter , Häußling Lukas , Ringsdorf Helmut , Bubeck Christoph , Neher Dieter
Published: May 2005

Ordered structures of donor‐acceptor substituted polyenes (see Figure, where R'=phenyl or anthryl) formed using the Langmuir‐Blodgett technique are reported. The mono‐ and multilayers have been traansferred to solid supports and their nonlinear optical characteristics examined using angledependent second harmonic generation (SHG).

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Porous silicon – what is responsible for the visible luminescence?
Authors: Sailor Michael J. , Kavanagh Karen L.
Published: May 2005

Size‐dependent quantum confinement effects have been invoked to explain the occurrence of vislble luminescence in porous silicon and TEM data supports the existence of crystalline Si domains which have dimensions small enough that one could expect such phenomena. However, is this the whole story? Various proposed explanations are discussed, and the recent observations of luminenscence in Si colloidal suspensions examined.
meso‐(Tetraphenylporphinato)manganese(III)‐tetracyanoethenide, [MnIIITPP]::⊕[TCNE].⊖. A New Structure‐Type Linear‐Chain Magnet with a Tc of 18K
Authors: Miller Joel S. , Calabrese Joseph C. , McLean R. Scott , Epstein Arthur J.
Published: May 2005

Cooperative magnetic interactions in molecular materials at room temperature are the goal of much interdisciplinary research. The title compound is shown to have a Tc of 18 K and to be of a new structural type which makes it a suitable model for the previously reported, disordered, infusible V(TCNE), which is a room‐temperature magnet. The synthesis and structure of the new material are discussed.
New routes to Cu‐patterned teflon substrates
Authors: Hampden‐Smith Mark J. , Kodas Toivo T. , Rye Robert R.
Published: May 2005

In microelectronics, copper conductors and Teflon substrates are the materials of choice in many applications due to the high conductivity of copper and the low dielectric constant of Teflon. The nature of Teflon, however, results in low adhesion strength, which makes a multi‐step Cu‐deposition process necessary. Here, an alternative, selective CVD, which can produce smaller feature sizes and reduces the need for wet etching, is presented and explained.
New redox‐responsive cryptands containing tetrathiafulvalene units
Authors: Gasiorowski Rafal , Jorgensen Tine , Møller Jørgen , Hansen Thomas K. , Pietraszkiewicz Marek , Becher Jan
Published: May 2005

Cation‐sensitive electrochemically active systems have been provided with new potential model compounds in the form of recently synthesized TTF derivatives. The molecules, one of which is shown in the figure, are flexible and seem to be much better metal‐ion ligands than the previously reported TTF‐cage compounds.

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Phase‐matched optical second‐harmonic generation in Langmuir–Blodgett film waveguides by mode conversion
Authors: Flörsheimer Mathias , Küpfer Munfred , Bosshard Christian , Looser Herbert , Günter Peter
Published: May 2005

Phase‐matched second‐harmonk light generation by guided mode conversion has been observed for the first time in nonlinear optically active Langmuir‐Blodgett films. The sketch of the experimental setup (Figure) shows how the infrared fundamental beam is coupled via a grating into SiO2/TiO2‐DCNAP waveguides with various thicknesses of DCNAP film. The film with the correct thickness for phase matching guides a second‐harmonic mode, which is observed as a blue beam, as illustrated in a photograph in the article.

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Ion implanted material in highly integrated GaAs ICs
Authors: Myers Frederick A.
Published: May 2005

Selective ion implantation and epitaxy are beginning to increase the degree of integration of monolithic microwave ICs (MMICs). Most MMICs produced to date have only a single function per chip, for example the C‐band phased array radar T/R module illustrated in the Figure, but selective ion implantation has allowed a complex, multifunction GaAs MMIC to be realized recently.

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Ferroelectric thin films
Authors: Tossell David A. , Patel Anil
Published: May 2005

Lead‐based ferroelectric thin films have many potential pyroelectric and electro‐optic applications. Thin‐film‐based devices are very likely to replace their bulk wafer counterparts within the next few years, particularly where full integration with silicon technology becomes feasible. The sol‐gel route is shown to produce PST films with properties approaching those of the bulk, and dual ion beam sputtering is demonstrated to have the capability of significantly affecting the film density, stoichiometry, morphology and even the crystalline phase during the growth of PLZT thin films.
Review of Polymer Synthesis in 1992
Authors: Schlüter Arnulf‐Dieter
Published: May 2005

In last year's review of polymer synthesis (Nachr. Chem. Tech. Lab. 1992, 40, 221), particular attention was paid to publications on metathesis and Ziegler–Natta polymerization, emphasizing the stormy and far‐reaching developments in these areas of polymer synthesis. This year's review will also stress specific points of interest, the most important one being anionic polymerization, where much has happened. Additionally, progress in other very different and less extensive areas of polymer synthesis will be presented. Like last year, areas of work in which polymers have been synthesized with new types of molecular structures will be somewhat preferentially treated.
Polymeric materials: A review of progress in 1992
Authors: Meyer Wolfgang H.
Published: May 2005

Developments in polymeric materials in 1992 were characterized by small but important steps achieved as the result of much detailed work. Increasing attention is being paid to the supramolecular structure of the materials with the aim of producing ever smaller well‐defined systems. Examples cited in the review include the use of well‐defined dispersions of conducting polymers, liquid crystalline polymers, nanostructured polymer alloys and composites to make materials with better processing characteristics and greater chemical or physical stability.
Review of Polymer Physics 1992
Authors: Ewen Bernd
Published: May 2005

Advances in polymer physics are discussed, including the latest insights into the morphology of polymeric systems, small‐angle X‐ray studies of liquid‐crystalline polymers, and the influence of chain branching on the thermodynamic and hydrodynamic properties of polymer solutions and melts. Among the newly developed or adapted methods, NMR imaging can be used to calculate the stress distribution in a test strip of polymer, as shown in the Figure.

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A new fluorescence probe for network formation with interesting nonlinear optical properties
Authors: Bollaert Vera , De Schryver Frans C. , Tackx Peter , Persoons André , Nusselder Jan Jaap H. , Put Jos
Published: May 2005

Molecular sensors can be used to monitor the polymerization of linear precursors and also the formation of epoxy networks. The synthesis and properties of a novel fluorescence probe, tris(p‐isocyanatophenyl)amine (TIPA), which acts both as a crosslinking site and as a chemical sensor, are described. A dramatic change of fluorescence intensity coupled with the high second‐order hyperpolarizability of TIPA and its urethane derivative make it promising for the synthesis of nonlinear optical thermosets whose degree of curing and the mobility of the crosslink points can be measured by luminescence.
Optical second‐harmonic effect of sol–gel inorganic–organic nanocomposites
Authors: Kador Lothar , Fischer Reiner , Haarer Dietrich , Kasemann Reiner , Brück Stefan , Schmidt Helmut , Dürr Heinz
Published: May 2005

Second‐order nonlinear optically (NLO) active materials have promising technical applications in optoelectronic devices. A general problem in NLO‐active polymeric systems is the decay of orientational order with time. Results are presented which show that using inorganic–organic composite materials produced by the sol–gel process as a rigid matrix for oriented χ(2) chromophores (Figure) may provide a means of overcoming this problem.

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An “omega” energy filtering TEM— Principles and applications
Authors: Probst Wolfgang , Benner Gerd , Bihr Johannes , Weimer Eugen
Published: May 2005

An energy filtering transmission electron microscope (EFTEM) has the advantage that, unlike a conventional TEM, it can also utilize the spectroscopic information carried by inelastically scattered electrons, thus making optimum use of all the available information. The design of an EFTEM featuring an Ω‐type imaging electron‐energy‐loss spectrometer that is integrated into the imaging beam path is described, and its modes of use and possible applications discussed.
Understanding the user
Authors: ter Mors Rob
Published: May 2005

Elsevier belongs to one of the largest scientific publishing groups in the world. This “Fall Publications in Materials” issue, which contains extended coverage of new books and journals as well as an increased number of book reviews, is introduced by the head of physics and materials science marketing at Elsevier in Amsterdam. Will be traditional journal concept become obsolete? Will the various on‐line services be compatible? Will on‐line “journals” be peer‐reviewed? The answer to these questions will only be found by understanding the user.
Synthesis and structural studies of the perovskite‐related compound YBaCo2O5 + x
Authors: Zhou Wuzong , Lin Cheng Tian , Liang Wei Yao
Published: May 2005

A new perovskite‐related compound, YBaCo2O5, is reported, which has a basic structure which is tetragonal and isomorphous with YBaCuCoO5. Excess oxygen can be introduced into the anionic sites in the yttrium layer, an effect which could be important in the development of the material as a redox catalyst and a charge carrier reservoir in high‐Tc superconductors as part of a superlattice formed with a superconducting phase. The preparation of the new material and the analysis of its structure are reported.
PEO intercalation in layered chalcogenides
Authors: Ruiz‐Hitzky Eduardo , Jimenez Ricardo , Casal Blanca , Manriquez Victor , Ana Angélica Santa , Gonzalez Guillermo
Published: May 2005

Intercalated materials the electronic framework behavior of a semiconducting host lattice with the ionic‐conductivity properties of poyethyleneoxide/alkali‐metal guest species are reported. Such materials are of interest for use in solid‐state high‐energy batteries. Here, layered transition metal chalcogenides serve as the host materials, polyethyleneoxide being intercalated by two different methods.
Electroluminescent devices based on poly(methylphenylsilane)
Authors: Suzuki Hiroyuki , Meyer Harald , Simmerer Jürgen , Yang Jiping , Haarer Dietrich
Published: May 2005

The fabrication of high‐efficiency light‐emitting diodes (LEDs) based on sublimed molecular films has attracted much attention in the search for materials for application in large‐area flat‐panel displays. Here, multilayered LEDs based on poly(methylphenylsilane), PMPS, as the hole transporting material are reported (see Figure). In contrast to polyphenylenevinylene, PMPS films exhibit a high effective mobility of holes, making the material suitable for fast switching applications.

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Nonplanar tetrathiafulvalene vinylogues
Authors: Kato Hiroshi , Kobayashi Tomoshige
Published: May 2005

Planarity of the components of conducting charge‐transfer (CT) complexes has been thought to be necessary in order to maximize overlap. Recently, a number of distorted, nonplanar tetrathiafulvalene (TTF) analogues (e.g. see Figure) have been prepared and found to be viable compounds for the formation of CT complexes. Recent progress is discussed.

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Electronic origin of scanning tunneling microscopy images and carbon skeleton orientations of normal alkanes adsorbed on graphite
Authors: Liang Weigen , Whangbo Myung‐Hwan , Wawkuschewski Aleksander , Cantow Hans‐Joachim , Magonov Sergei N.
Published: May 2005

STM images of organic insulating molecules adsorbed on conducting substrates can only be understood if their electronic origin is known. Images of normal alkanes on graphite (n‐C36H74) is shown in the Figure are interpreted here on the basis of their partial electron density plots ρ(r0,ef), demonstrating that the linear alkanes can “tumble” and change their orientation with respect to the graphite surface.

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STM study of molecular order and defects in the layers of cycloalkanes (CH2)48 and (CH2)72 adsorbed on graphite
Authors: Wawkuschewski Aleksander , Cantow Hans‐Joachim , Magonov Sergei N. , Möller Martin , Liang Weigen , Whangbo Myung‐Hwan
Published: May 2005

Cycloalkanes adsorbed on graphite, unlike the normal alkanes considered in the preceding contribution, cannot undergo a tumbling motion and change their orientation with respect to the graphite surface. The orientation of the cycloalkanes as revealed by STM images is reported and lamella defects are identified. An answer is also given to the question of how many adlayers are seen by STM, which is very important in the interpretation of superstructure patterns.
The deformability of the thiophene ring: A key to the understanding of the conformational properties of oligo‐ and polythiophenes
Authors: Barbarella Giovanna , Zambianchi Massimo , Bongini Alessandro , Antolini Luciano
Published: May 2005

Oligothiophenes in solution and in the solid state have different conformational properties, as can be concluded from the spectroscopic and theoretical data and X‐ray structure of three di‐ and tetramethyl α‐conjugated quaterthiophenes (see Figure) reported here.

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Molecular recognition of alkali‐ions by crown‐ether‐functionalized poly(alkylthiophenes)
Authors: Bäuerle Peter , Scheib Stefan
Published: May 2005

New crown‐ether‐functionalized alkyl(oligothiophene)s (see Figure) have been synthesized and electropolymerized to alkali metal ion sensitive poly(alkylthiophene)s. It is shown for the first time that the redox chemistry of a conducting polymer is strongly influenced by the specific host‐guest interaction, although the crown ether units are not π‐conjugated to the conducting backbone but separated by an insulating oxa‐alkyl chain.

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Fullerene polymers
Authors: Hirsch Andreas
Published: May 2005

Polymeric fullerene materials come in tree main types: “pendant”, where C60 is attached to the side chain of a polymer (see Figure) or to the surface of a solid, “dendritic”, and “in‐chain”, where the fullerene forms part of the main chain. The synthesis of the various types is discussed and their expected unique properties described.

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Sensor materials for solvent vapor detection—donor–acceptor and host–guest interactions
Authors: Dickert Franz L. , Haunschild Alexander
Published: May 2005

Sensors for a huge variety of detection tasks can be made by combining chemically sensitive materials with microstructured physical devices. How individual analyte species can be recognized using host–guest binding schemes (the Figure shows a paracyclophane host molecule) and how categories of compounds can be identified using sensors that respond to different functionalities are reviewed.

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Phenyl groups as molecular fasteners: Phenyltelluro‐substituted tetrathiafulvalenes
Authors: Khodorkovsky Vladimir Y. , Wang Changsheng , Becker James Y. , Ellern Arkady , Shapiro Lev , Bernstein Joel
Published: May 2005

Phenyltelluro–tetrathiafulvalene (TTF) derivatives, for example those shown in the Figure, are reported to exhibit one‐component two‐dimensional networks of shortened molecular interactions and electrical conductivities that are unsually high for neutral organic molecules. Evidence for stacking of TTF groups—despite the bulky phenyl groups—is presented.

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Plasma induced chemical vapor deposition of Zr(C,B) from CpZr(BH4)3 (Cp  C5H5⊖)
Authors: Reich Silvia , Messelhäuser Johannes , Suhr Harald , Erker Gerhard , Fritze Cornelia
Published: May 2005

The hardness of metal borides makes them suitable for applications as corrosion resistant and, in combination with other materials, as hard coatngs for cutting tools, for example. The plasma induced chemical vapor deposition of Zr(C,B) from the precursor CpZr(BH4)3, where Cp is C5H5⊖, is described and the results of an investigation of the dependence of the deposition rete and the film characteristics on the deposition parameters, e.g. the carrier gas and the substrate temperature, are presented.
Materials Science in Spain
Authors: González Domingo
Published: May 2005

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.
Immobilization of functionalized lipids in a random poly(methacrylate) copolymer monolayer
Authors: Lowack Klaus , Helm Christiane A.
Published: May 2005

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.

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On the nature of methyltrioxorhenium(VII) encapsulated in zeolite Y
Authors: Malek Andrzej , Ozin Geoffrey
Published: May 2005

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.
Paramagnetic nematic liquid crystals with an iron core
Authors: Marcos Mercedes , Serrano José Luis , Alonso Pablo J , Martínez Jesús I.
Published: May 2005

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.
Layered ceramics
Authors: Moya José S.
Published: May 2005

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.

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Polymeric drug delivery systems
Authors: Román Julio San , Gallardo Alberto , Levenfeld Belén
Published: May 2005

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.

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CH…S and S…S: Two major forces in organic conductors
Authors: Novoa Juan J. , Rovira M. Carme , Rovira Concepció , Veciana Jaume , Tarrés Judit
Published: May 2005

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H…X and S…S are the two interactions most likely to influence the structures of these materials.
Substituted Rigid Rod‐Like Polymers—Building Blocks for Photonic Devices**
Authors: Neher Dieter
Published: May 2005

Substituted rigid rod‐like polymers (RRPs) can be exploited to control the microscopic order in, and the fabrication of, devices with potential uses in photonics. The supermolecular structures formed by these interesting materials (e.g. see Figure) are considered, attention being focused on the correlation between structural properties and macroscopic properties such as nonlinear susceptibilities

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Photochemical fabrication of nonlinear optical polymer waveguides
Authors: McCulloch Iain , Boudoughian George , Man Hong‐Tai
Published: May 2005

Waveguides based on methacrylate polymers containing active dinitrostilbene chromophores have been fabricated by photobleaching using a xenon lamp. The efficiency of photobleaching, as well as the effective refractive index changes obtainable, represent a singnificant improvement over currently used materials, single‐mode waveguides being formed with a optical loss of less than 1 dB cm−1.
Photoelectron and optical spectroscopic investigations of the electronic structure of oligo(p‐phenylenevinylene)s in the solid state**
Authors: Schmidt Albert , Anderson Michele L. , Dunphy Darren , Wehrmeister Thomas , Müllen Klaus , Armstrong Neal R.
Published: May 2005

The performance of organic light‐emitting diodes based, for example, on poly(p‐phenylenevinylene) could be more easily optimized on the basis of a thorough knowldge of the energies of the electron affinities and the ionization potentials of the materials. Here, results from UV‐photoelectron spectroscopy are presented which allow the determination of the absolute binding energies of the occupied molecular orbitals of oligo‐PPV. These results are compared with values calculated using semiempirical methods.
Synthesis of novel polymers containing cyclobutadiene thiophene and alkyne units: polymeric organometallic mesogens**
Authors: Altmann Markus , Enkelmann Volker , Lieser Günther , Bunz Uwe H. F.
Published: May 2005

A new class of organometallic liquid‐crystalline rigid‐rod polymers containing thiophene (see Figure) are reported and it is shown how their phase behavior can be tuned through variation of the side groups. The crystallization of the compound shown in the Figure proceeds through a transient lyotropic smectic state, a state hitherto unknown in polymeric organometallic systems

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Noble metal loaded block lonomers: micelle organization, adsorption of free chains and formation of thin films**
Authors: Spatz Joachim P. , Roescher Arno , Sheiko Sergei , Krausch Georg , Möller Martin
Published: May 2005

Monitoring the formation of ultrathin films by scanning force microscopy provides information, for example, on the concentration dependence of the film structure (the Figure shows micelle agglomeration from high concentration solutions to form a layer with holes) and insight into the process from micelle formation to structural transformation in the films

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Origins of the spontaneous magnetization in MnPS3 Intercalates: A Magnetic Susceptibility and Powder Neutron Diffraction Study**
Authors: Evans John S. O. , O'Hare Dermot , Clement René , Leaustic Anne , Thuéry Pierre
Published: May 2005

A link between metal vacancy sites and magnetic ordering in the ion exchange intercalates of MnPS3 has been established. High‐temperature X‐ray pattersn show that the formation of a metal vacancy superstructure and the transition to the magnetically ordered state are intimately linked, providing strong evidence that spontaneous magnetization results from the imblanace of spins on the two sublattices of the antiferromagnetically ordered host lattice leading to net ferrimagnetism.
The federation of materials societies
Authors: Laudise Robert A.
Published: May 2005

The interests of the materials community in the US are represented by the Federation of Materials Socieites (FMS), in umbrella organization that is particularly concerned with the exchane of information between the policy‐making community and the materials community. The FMS's structure, aims, publications and activities, such as workshops and conferences, are briefly outlined and its technology policy recommendations described in more detail.
Electroluminescence, photoluminescence and x‐ray reflectivity studies of self‐assembled ultra‐thin films*
Authors: Hong Haiping , Davidov Dan , Chayet Haim , Avny Yair , Faraggi Erez Z. , Neumann Ronny
Published: May 2005

High‐qality self‐assembled heterostructures for polymer LEDs have been fabricated from PPV and newly synthesized copolymers of PPV and naphthalene. It is shown that the layer‐by‐layer self‐assembly of multilayer structures has advantages with respect to control of the thickness and homogeneity of the polymer films compared to the conventional spin coating technique. The fabrication and characterization of the heterostructures are detailed and features of the electroluminescence and photoluminescence discussed.
Photo‐crosslinking in freely‐suspended films of ferroelectric lc‐polymers*
Authors: Brehmer Martin , Zentel Rudolf , Reibel Jürgen , Decher Gero
Published: May 2005

The combination of thin‐film and ferroelectric‐elastomeric properties—of interest for piezoelectric and nonlinear optical applications—is the aim in preparing freely‐suspended (FS) films from polymeric liquid‐crystal elastomers with SmC* phases. The preparation and characterization of such films from crosslinkable SmC* polymers is reported for the first time, together with their photo‐crosslinking and an investigation of the stabilization effect of the crosslinking.
Change in the shape of copper nanoparticles in ordered phases
Authors: Tanori Judith , Paule Pileni Marie
Published: May 2005

The shape of copper metal particles (see Figure) is demonstrated to depend on the structure of the mesophase (cylindrical reverse micelles, interconnected networks of surface aggregates or lamellar phases) i the surfactant system used as a microreactor for their synthesis. An understanding of this correlation is of great importance for magnetic recording technology

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Synthesis and characterization of micrometersized polypyrrole‐coated polystyrene latexes*
Authors: Lascelles Stuart F. , Armes Steven P.
Published: May 2005

Improvements in the processability of polypyrrole—a relatively air‐stale organic conducting polymer—can be obtained by producing colloidal dispersions. The particles reported here are “inside out”, i.e., micrometer‐sized, sterically stabilized polystyrene latex particles are coated wh an outer layer of polypyrrole. Their synthesis and physical properties are described and ideas for further work and potential novel applications, for example in immunodiagnostic assays, suggested.
The preparation of novel silica gel hollow tubes**
Authors: Nakamura Hidenori , Matsui Yasushi
Published: May 2005

Work‐like silica gel hollow tubes have been prepared using a sol‐gel method. The tubes (see Figure), wich are porous, mostly have one end closed, although occasionally tubes with both ends closed are produced. The preparation method, which involves the hdyrolysis of tetraethylorothosilicate in a mixture of ethanol, ammonia, water and citric acid monohydrate, is described

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Ion beam induced charge microscopy for the analysis of integrated circuits
Authors: Breese Mark
Published: May 2005

Ion beam induced charge (IBIC) microscopy provides a means of imaging the depletion layers of working microelectronic devices beneath their thick metallizaion and passivation layers. The concept of IBIC microscopy is outline, its advantages over optical and electron microscopy techniques are outlined, its advantages over optical ad electron micorscopy techniques are described, and examples of images are presented. One particular application is as a way of identifying device components that are susceptible to having their logic state altered by cosmic rays when used in satellites, for example.
Charge transport polymers for light emitting diodes*
Authors: Li Xiao‐Chang , Yong Tuck Mun , Cacialli Franco , Grüner Johannes , Friend Richard H. , Holmes Andrew B. , Giles Mark , Moratti Stephen C.
Published: May 2005

Electron transport polymers containing aromatic oxadiazole side chain chromophores have been designed and synthesized. They have been found useful for improving the quantum efficiency, lowering the turn‐on voltage, and enabling the use of the more stable aluminum cathode in the fabrication of polymer LEDs. As the oxadiazole units are chemically bound to the polymer chain, rather than being simply dispersed in a polymer matrix, the materials are expected to exhibit long‐term morphological stability. The synthesis and several different applications are presented.
Ultraviolet electroluminescence from an organic light emitting diode
Authors: Berggren Magnus , Granströim Magnus , Inganas Olle , Andersson Mats
Published: May 2005

The extension of the emission region or organic LEDs into the ultraviolet region is reported. Emission at 394 nm is achieved by modifying the geometry of a device based on poly(octylphenyl)bithiophene (PTOPT) and poly(octylphenyl)oxadiazole (PBD) which had previously been shown to emit white light. Through changing the geometry the red and green emission peaks have been suppressed and the UV band (from the PBD) enhanced

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Polarized photoluminescence of liquid crystalline polymers with isolated arylenevinylene segments in the main chain*
Authors: Wendroff J. H. , Lüssem Georg , Festag Reiner , Greiner Andreas , Schmidt Claudia , Unterlechner Christoph , Heitz Walter
Published: May 2005

Anisotropic charge transport, or polarized photo‐ and electroluminescence are possible applications for materials combining the optical properties of arylenevinylene polymers with the characteristic orientational order of the liquid‐crystalline state. Thermally stale, soluble materials with a broad mesophase, which can be oriented macroscopically using conventional processing techniques and when exhibit highly anisotropic luminescence behavior of use in polarized LEDs are presented.
Skeletons in the cupboard: Rediscovery in science
Authors: Oliver Scott , Ozin Geoffrey A. , Ozin Linda A.
Published: May 2005

Are the ideas behind the recently published developments in biomimetic inorganic materials chemistry really as novel as they seem? This article is about rediscovery in science. The focus is on biomimetic inorganic materials chemistry and the 1872 classic published work of Pieter Harting, a Dutchman from Utrecht, on synthetic morphologies, particularly artificial calcareous formations. It would seem that one of the founding fathers of this burgeoning field of endeavor has (almost) been forgotten.
Doped and heteroatom‐containing fullerene‐like structures and nanotubes
Authors: Tenne Reshef
Published: May 2005

A review of the current knowledge on carbon fullerenes doped with foreign atoms and heteroatom‐containing fullerene‐like structures and nanotubes is provided. Strong covalent bonds lend high specificity and stabilize the hollow‐cage and symmetric structure of these moieties. These structures are distinct from noble‐gas and metallic clusters, where either weak van der Waals forces or stronger metallic bonds, which are not very specific, hold the cluster atoms together. In the latter kind of clusters, atoms gain stability through close packing and large coordination numbers and consequently they cannot afford a hollow core. Nonetheless some intermetallic nanoparticles exhibit truncated icosahedral symmetry. The field is divided, somewhat artificially, into two separate categories. One family consists of fullerene‐like clusters assembled from different atoms which do not have a bulk counterpart of similar chemical formula. The other group is that of fullerene‐like nanostructures which are obtained mainly from ubiquitous 2‐D layered compounds; various elements and compounds with 3‐D character and also from certain metallic alloys. It is shown that nanoparticles of 2‐D compounds are unstable in the planar form and they reconstruct into hollow‐cage nanoparticles, spontaneously. Nanosolids of this kind may reveal vastly different properties from their bulk predecessors. Numerous applications for the doped and heteroatom fullerene‐like materials in the fields of catalysis, lubrication, electronic and photonic devices, alternative energy sources, etc. are expected upon further study and development.
Synthesis and linear optical spectroscopy of thioflavylium near‐infrared absorbing dyes
Authors: Chen Chin‐Ti , Marder Seth R.
Published: May 2005

Near‐infrared adsorbing dyes have potential applications in optical recording and printing technology which employs inexpensive semiconductor lasers that emit light around 800 nm. A convenient and high yield synthesis of thioflavylium chromophores is presented, materials which are found to act as a powerful acceptor for creating such near‐IR absorbing dyes.
Thermochromic composites and propagating polymerization fronts
Authors: Nagy Istvan P. , Sike Laszlo , Pojman John A.
Published: May 2005

Remote temperature sensing has been recently achieved using a new composite material produced using a propagating front of polymerization. The use of this polymerization technique for preparing uniform materials from components which phase separate upon reaction, and the properties and potential applications of the resulting materials are discussed.
Chromophore‐zeotype composites: Direct synthesis of an array of strictly aligned metal‐organic complex chromophores in a crystalline silica matrix
Authors: Behrens Peter , van de Goor Gianpietro , Marlow Frank , Hoffmann Katrin , Kallus Stefan , Schüth Ferdi
Published: May 2005

Chromophores embedded in zeolite‐type hosts have potential applications in optical devices. However, the conventional preparation results in an inhomogeneous distribution of the chromophores. It is demonstrated that direct synthesis can result in chromophore‐zeolite composites with well‐defined stoichiometry and uniform chromophore distribution, as illustrated for [CocpF⊕]‐NON in the figure.

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Organic two‐dimensional templates for the fabrication of inorganic nanostructures: Organic/inorganic superlattices
Authors: Kimizuka Nobuo , Kunitake Toyoki
Published: May 2005

The self‐organization of inorganic precursors in predetermined patterns is the first step towards the ability to synthesize mesoscopic inorganic materials. Several techniques are described, including the immobilization of inorganic precursors by coordination with bilayer ligands (see figure), which led, for example, to a novel Cd4Br12S cluster. Finally, the formation of organic/inorganic superlattices is outlined.

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Alignment of single‐crystal zeolites by means of microstructured surfaces
Authors: Scandella Loris , Binder Gunnar , Gobrecht Jens , Jansen Jacobus C.
Published: May 2005

Nanoscale devices based on zeolites require either thin films of single‐crystalline zeolites or ordered arrangements of zeolite crystals. A novel technique—with potentially wide applications—is reported here that enables thousands of zeolite crystals to be ordered using a microstructured silicon surface. The figure shows zeolites oriented in two positions (marked A and B) in silicon grooves.

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Continuous yttria‐stabilized zirconia fibers
Authors: Clauss Bernd , Grüb Andrea , Oppermann Wilhelm
Published: May 2005

Polycrystalline oxide fibers have not yet been exploited to their full potential, perhaps because of difficulties with processability. In the successful new route for the production of continuous yttria‐stabilized zirconia fibers detailed here, ZrO2 particles sols are used as oxide‐forming components. The fine‐grained compact ceramic fibers of tetragonal zirconia polycrystals obtained 2 mol‐% Y2O3 are shown in the figure.

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A single source approach to the synthesis of CdSe nanocrystallites
Authors: Trindade Tito , O'Brien Paul
Published: May 2005

Synthetic routes to semiconductor nanocrystallites have become of particular interest since nanoparticle devices have been constructed. The route reported here for CdSe uses a single source in tri‐n‐octylphosphine oxide instead of the hazardous metal alkyls conventionally employed. The characterization of the nanocrystallites (see figure) shows that they are crystalline, approximately spherical, and close to monodispersed.

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Chemical synthesis of nanocrystalline titanium and nickel aluminides from the metal chlorides and lithium aluminum hydride
Authors: Haber Joel A. , Crane Johanna L. , Buhro William E. , Frey Claire A. , Sastry Shankar M. L. , Balbach John J. , Conradi Mark S.
Published: May 2005

Aluminide intermetallics are potentially useful structural materials—provided their brittleness can be reduced. One possible method is the refinement of grain size to the nanometer level. Measurements of the mechanical properties are required in order to confirm this. The preparation described here is a general solution‐based strategy for the chemical synthesis of nanocrystalline aluminide intermetallics. The results of sample characterization are presented and a two‐step formation of the aluminide phase proposed.
Origin of the “ohmic” current in organic field‐effect transistors
Authors: Horowitz Gilles
Published: May 2005

Efforts to improve organic field‐effect transistors (OFETs) have so far concentrated mainly on their field‐effect mobility, but another important parameter is the on–off ratio, i.e., the ratio of the saturation current at maximum absolute gate voltage (Vg) to that at zero Vg. It is shown how an understanding of the so‐called “ohmic” current, which reduces this ratio, will perhaps lead to improved performances now it has been recognized that this current is connected with mobile dopants.
Hierarchical inorganic materials
Authors: Kresge Charles T.
Published: May 2005

The synthesis of hierarchical inorganic–organic composites using biological design principles is a domain where materials chemists are usually out‐smarted by Nature. The author summarizes and discusses the recent contributions made by the groups of Geoffrey Ozin in Toronto (Canada) and Stephen Mann in Bath (UK) to the generation of matter with a striking resemblance to the highly complex forms characteristic of inorganic biological structures.
The impact of interdisciplinary materials science
Authors: Gregory Peter
Published: May 2005

How “hot” is published research? The Institute of Scientific Information (ISI), an independent organization from the USA, follows the citation behavior of scientists on a regular basis. Which journals do they cite? How often? Which journals are cited the most? Which papers in which journals are cited immediately on publication? The ISI has recently published its evaluation for 1994. The performance of Advanced Materials is discussed.
Two novel thermotropic liquid crystalline substituted oligo(p‐phenylene‐vinylene)s: Single crystal X‐ray determination of an all‐trans oligomeric PPV
Authors: Gill Richard E. , Meetsma Auke , Hadziioannou Georges
Published: May 2005

Conjugated polymers, for example PPV and polythiophene, show great potential for applications in thin‐film microelectronic and optoelectronic devices. An understanding of structure–property relationships in these materials is therefore of great importance. Here, the successful preparation of two novel substituted five‐ring oligo‐PPVs and the first crystallographic characterization of a single‐crystal all‐trans PPV oligomer are reported.
Donor–acceptor substituted tetraethynylethenes
Authors: Tykivinski Rik R. , Schreiber Martin , Seiler Paul , Diederich François , Gramlich Volker
Published: May 2005

A comprehensive series of donor/acceptor substituted tetraethynylethenes has been prepared by palladium‐catalyzed acetylenic coupling. The conjugated C‐atom scaffolds of these remarkably stable compounds are planar, including the substituted phenyl rings. Trends in electronic, optical, and structural properties as a function of degree and pattern of substitution are reported and the effectiveness of intramolecular donor–acceptor interactions via linear conjugation paths and cross‐conjugation paths compared.
Structure‐property relationships in nonlinear optical tetraethynylethenes
Authors: Bosshard Christian , Spreiter Rolf , Günter Peter , Trkwinski Rik R. , Schreiber Martin , Diederich François
Published: May 2005

The third‐order nonlinear optical properties of donor‐acceptor substituted tetraethynylethenes (see figure and also the preceding contribution) are presented with special emphasis on the structure‐property relationships and the effect of conjugation paths on the optical nonlinearity. In one single class of materials the influence of donor‐acceptor substitution as well as of full two‐dimensional conjugation on the third‐order nonlinearity is clearly shown.

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