Surface characterization of ion-implanted polyethylene

Polyethylene (PE) film was implanted with 1000-keV Ar⁺ ions to a fluence of 5 × 10¹⁴ ions/cm² under high vacuum conditions (2.5 × 10⁻⁶ torr) and the film surface was investigated by means of microhardness and microwear measurements, and FTIR/ATR, Raman, and XPS techniques. Ion implantation significantly increased the subsurface hardness and also significantly improved the microwear resistance of the polymer. The implanted surface region of the film was found to consist of two distinct layers. One was the outermost carbon layer with a thickness of the order of 10 nm. In this layer, ca. 75% of carbon atoms were combined by graphitic sp² and diamond-like sp³ bonds, and the remaining 25% had chemical links with oxygen atoms. Spectroscopic data suggested that the sp²-bonded carbons segregated in graphite-like clusters containing imbedded oxygen atoms, interconnected by the sp³-bonded carbons. The other was the subsurface layer resulting from PE oxidation after ion-beam treatment. This layer was characterized by high contents of O H and CO groups as well as ester and double bonds. The chemical composition of the layer was uniform and did not vary over the layer thickness of about 1.4 μm. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 715–725, 1998     

Electrochemical characterization for ion-implanted materials surfaces

Studies on the surface modification of materials by ion implantation have been carried out during the past 25 years in RIKEN. In this paper, results of electrochemical studies on the ion-implanted materials are described to realize the unique substances formed by the ion implantation. The ion implantation is used for compositional and structural surface modification of iron and carbon substrates. Voltammetric behavior of ion-implanted iron electrodes characterized effects of the ion implantation on anodic dissolution and passivation properties of the modified surfaces. Typical electrode reaction properties of ion-implanted carbon electrodes clearly were related to the effects of structural modification of the carbon surfaces.     

Microstructural and auger microanalytical characterization of Cu-Hf and Cu-Ti catalysts.

Degradation processes occurring at the surface and in the bulk of Cu-based amorphous alloys during cathodic hydrogen charging were used for promoting the catalytic activity of such alloys. These processes modifying the structure, composition, and morphology of the substrate proved to be useful methods for transforming Cu-Hf and inactive Cu-Ti amorphous alloy precursors into active and durable catalysts. Indeed, their catalytic activity for dehydrogenation of 2-propanol increased up to a conversion level of approximately 60% at selectivities to acetone of about 99% for Cu-Ti and to conversion of approximately 90% at selectivities of approximately 95% for Cu-Hf. Previous attempts carried out by aging in air or hydrogen charging from the gas phase resulted in a maximum conversion level up to 15% for Cu-Hf and up to 3% for Cu-Ti. High resolution Auger spectroscopy allowed changes occurring during the activation process to be identified, namely, the formation of small Cu particles on the HfO2 surface and the formation of highly porous particles containing mostly Cu and some Ti and O (Cu-Ti-O) on a Cu-Ti substrate. Differences in the chemistry and structure of both catalysts are discussed, and the implications for catalytic function are considered. A probable configuration of active sites on the Cu-Ti-O/Ti-O-Cu catalyst for dehydrogenation of 2-propanol is proposed.     

Design, synthesis and characterization of monomolecular interfacial layers

We have designed a series of monomolecular films comprised of four basic structural motifs. We have used these films for a variety of purposes, ranging from support structures for chromophore arrays to the creation of selective and biomimetic interfaces. We will discuss the several different types of interfacial binding chemistry that are used in the construction of these interfacial films, for both monomeric and polymeric layer structures. Following a discussion of the construction of the adlayers, we describe several uses of these assemblies, in areas ranging from adsorption to optical signal processing, and the formation of biomimetic interfacial structures.     

Electrochemical deposition and characterization of copper-cobalt oxide layers by electrodeposition

The copper-cobalt oxide (Cu₂CoO₃) was successfully elaborated on indium tin oxide (ITO) substrate using the co-electrodeposition method in citric acid (C₆H₈O₇) solution at a temperature of 70 °C. The co-electrodeposition process of Cu₂CoO₃ thin films was realized by the electrochemical technique: cycle voltammetry. In this work, the effect of the cycle number on the cyclic voltammetry (CV), structural, and morphological of the Cu₂CoO₃ thin films were discussed. The (CV) showed that the current density of the co-electrodeposition of Cu₂CoO₃ decreases with the number of cycles. The X-ray diffraction (XRD) analysis revealed that the co-electrodeposition copper-cobalt oxide (Cu₂CoO₃) nanocrystallites with orthorhombic crystal structures. The analysis of the morphological surface by scanning electron microscopy (SEM) of copper-cobalt oxide indicated the formation of two types of crystals of different shapes: pyramidal and spherical corresponding to CoO₂ and Cu₂O respectively.     

Generation and characterization of surface layers on acoustically levitated drops

Surface layers of natural and technical amphiphiles, e.g., octadecanol, stearic acid and related compounds as well as perfluorinated fatty alcohols (PFA), have been investigated on the surface of acoustically levitated drops. In contrast to Langmuir troughs, traditionally used in the research of surface layers at the air-water interface, acoustic levitation offers the advantages of a minimized and contact-less technique. Although the film pressure cannot be directly adjusted on acoustically levitated drops, it runs through a wide pressure range due to the shrinking surface of an evaporating drop. During this process, different states of the generated surface layer have been identified, in particular the phase transition from the gaseous or liquid-expanded to the liquid-condensed state of surface layers of octadecanol and other related amphiphiles. Characteristic parameters, such as the relative permeation resistance and the area per molecule in a condensed surface layer, have been quantified and were found comparable to results obtained from surface layers generated on Langmuir troughs.     

Production and characterization of C and SiC layers on C fibres

Summary The construction, testing and operation of a semi-technical system for the multi-stage coating of endless fibres by means of thermally-activated CVD is described. One objective of this is to apply layer systems under conditions similar to those used in production with long-term reproducibility. Rovings coated in this way, for example, are made of high-tensile carbon fibres, and used as reinforcing components in the manufacture of modern composite materials. Research programs and laboratory test batches are characterized extensively by methods of surface and solid state analysis such as SEM, TEM, AES, XPS and RAMAN. Analytical investigations are supplemented by strength measurements made at several sites on the fibre coating and on the later application.     

Formation of Si-C-N ceramics from melamine-carbosilazane single source precursors

A series of melamine-carbosilazane pre-ceramic macromolecules (Mel-CSZs) were prepared by the condensation of melamine with different organochlorosilanes (R_xSiCl_4−x where R is CH₃/C₆H₅ and x is 1, 2 or 3) using pyridine as a solvent under nitrogen atmosphere. These melamine-based carbosilazane macromolecules (Mel-CSZs) were characterized by infrared spectroscopy (FT-IR), mass spectrometry (MS), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The backbone of the resulting Mel-CSZs consists of melamine and carbosilazane building blocks. Pyrolysis of these Mel-CSZs at 600 °C under nitrogen and vacuum afforded the corresponding silicon-based nonoxide carbonitride ceramics (Si-C-N). The microstructure and textural morphology of the resulting fine ceramic materials were examined using FT-IR, powder X-ray diffraction (XRD), and scanning electron microscopy (SEM).     

General survey and microanalytical aspects of ion-selective electrodes

Summary A survey is presented of recent developments in the field of ion-selective electrodes. Special emphasis is placed on problems of electrode miniaturization and ISFET production. Different electrode types in present use are described and theories for the interpretation of electrode mechanisms are outlined. It is pointed out that the electrode potentials are due to the formation of a space charge. Different applications of ion-selective electrodes are dealt with and the problems connected with the determination of small concentrations are discussed. Attention is given to the selection of conditions under which a reliable measurement of extremely small amounts or extremely small concentrations can be ensured.     

Surface- and microanalysis as a tool for studying the corrosion of aluminium

Corrosion phenomena of Al-1 % Si bond wires, observed after life testing of certain transistors, are studied. The following information is derived from laboratory simulation tests: the kinetics of the corrosion process, information about the corrosion mechanism and critical parameters, especially the influence of the environmental gas and Si content and finally the identification of the corrosion products and their comparison with those found for the transistor. It is demonstrated, using a combination of several surface analytical techniques, that the A1 pitting corrosion is induced and enhanced by the presence of water as a transport medium and surface electrolyte in an oxygen-rich atmosphere, with chloride ions as a stimulating and activating species. The effect of 1 % Si in the wire consists in acceleration of the corrosion rate, and is probably due to grain boundary effects. All critical corrosion parameters could be traced in the transistor system by electron microscopy, laser microprobe mass analysis and residual gas (and moisture) analysis by mass spectrometry.     

Simultaneous microanalytical determination of carbon,hydrogen and sulphur

Summary A microanalytical procedure for simultaneous determination of carbon, hydrogen and sulphur by combustion in a nitrogen atmosphere is described. The substance is oxidized by the thermal degradation products of silver permanganate (Körbl catalyst) which serve as a source of oxygen and as an absorbent for sulphur oxides. The carbon and hydrogen are determined by the classical methods and sulphur is converted into benzidine sulphate. The procedure is accurate, simple and quick.

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Zusammenfassung Ein mikroanalytisches Verfahren zur gleichzeitigen Bestimmung von C, H und S durch Verbrennung in Stickstoffatmosphäre wurde beschrieben. Die Substanz wird mit dem thermischen Zersetzungsprodukt von Silber-permanganat (Körbl-Katalysator) oxydiert, der als Sauerstoffdonator und als Absorbens für Schwefeloxide dient. C und H werden nach der klassischen Arbeitsweise bestimmt und S in Benzidinsulfat umgesetzt. Das Verfahren ist genau, einfach und rasch.

     

Chemical microanalytical systems: objectives and latest developments

Chemical microanalysis systems are at a very early state of development. At the present time a modular approach with subsystems carrying out the various functions such as sampling, preparation and measurement seems to be favored by the developers. The marketpotential of the systems can be seen primarily in the area of inexpensive monitoring equipment for environmental and process control. Reduction of size leads also to smaller sample volumes, less waste and shorter analysis time: Miniaturization is in many cases an essential feature for biological and in-vivo medical investigations, while some properties inherently associated with miniaturization can also lead to substantial improvements in the technical performance of the microsystem as compared to its macro version. This will be demonstrated by discussing some microsystems which include spectroscopic detection systems:– Miniature separation instruments coupled with advanced miniaturized detection device based on photothermal spectroscopy– Integrated-optical NIR evanescent wave sensor systems– Optochemical and biosensor systems     

Modulated electron emission for structural characterization of buried layers and interfaces

Principles and performances of Primary-beam Diffraction Modulated Electron Emission are briefly reviewed. This approach exploits the spatial modulation of the beam electrons waves intensity in ordered atomic arrays, which in turn results in a marked dependence of the electron emission on the incidence angle. Detection of Auger electrons or inelastically backscattered electrons (ionization losses) provides chemical specificity. Surface sensitivity is related to the inelastic mean free path of the detected electrons. Examples are given of the capability of this technique for structural characterization of buried layer and interfaces. They include: i) epitaxial growth of Co oxide on the (001) surface of Co bct film, ii) subsurface behaviour of Co epitaxial layers during the bct→hcp phase transition.     

Chemical microanalytical systems: objectives and latest developments

Chemical microanalysis systems are at a very early state of development. At the present time a modular approach with subsystems carrying out the various functions such as sampling, preparation and measurement seems to be favored by the developers. The marketpotential of the systems can be seen primarily in the area of inexpensive monitoring equipment for environmental and process control. Reduction of size leads also to smaller sample volumes, less waste and shorter analysis time: Miniaturization is in many cases an essential feature for biological and in-vivo medical investigations, while some properties inherently associated with miniaturization can also lead to substantial improvements in the technical performance of the microsystem as compared to its macro version. This will be demonstrated by discussing some microsystems which include spectroscopic detection systems:- Miniature separation instruments coupled with advanced miniaturized detection device based on photothermal spectroscopy- Integrated-optical NIR evanescent wave sensor systems- Optochemical and biosensor systems     

Some microanalytical uses of small-diameter charged-particle beams

Résumé Il est souvent nécessaire d'obtenir des renseignements analytiques sur des échantillons de faible volume soit pour caractériser qualitativement ou quantitativement des microquantités de matière, soit pour permettre l'étude des variations locales de composition. Les flux de particules chargées produits par les accélérateurs à haut voltage peuvent être focalisées jusqu'à des diamètres de quelques microns permettant ainsi d'appliquer à l'analyse de faible volume de nombreuses méthodes d'activation aux particules chargées par réactions nucléaires. Les renseignements analytiques peuvent être tirés de l'examen sélectifs des radiations émises durant l'irradiation aux particules chargées ce qui peut inclure la diffusion élastique, les particules chargées émises, l'émission γ et X. Les variations locales de concentrations d'un élément peuvent être suivies en balayant la surface de l'échantillon par le faisceau d'ions, soit par un mouvement mécanique de l'échantillon, soit par déflection du faisceau. Les techniques avec un micro faisceau sont maintenant utilisées pour obtenir des résultats sur des matériaux métallurgiques minéralogiques et semi-conducteurs.      

Solvothermal synthesis and characterization of new aluminophosphate layers templated by imidazolium ions

Two imidazolium templated aluminophosphate layers [N₂C₃H₅]₂ [Al₃P₄O₁₆H] (1) and [N₂C₃H₅] [AlP₂O₈H₂(OH₂)₂] (2) have been synthesized under solvothermal conditions at 160°C. The effects of P/Al ratio the amount of organic amine and the type of solvent on the products are investigated. Their structures are characterized by single-crystal X-ray diffraction (XRD) powder XRD ²⁷Al DOR NMR ³¹P MAS NMR and thermal analyses. Both compounds exhibit unusual structure architectures which are different from previously reported [Al₃P₄O₁₆]^3- and [AlP₂O₈]^3- families. Compound 1 crystallizes in the triclinic space group of P1̄ (No. 2) with a=8.940(2), b=9.360(2), c=11.721(2) Å, α=97.10(2), β=95.10(2), γ=91.91(2)°, V=968.4(3) Å³ and Z=2. The structure contains a new macroanionic inorganic sheet characterized by a series of double six-membered ring (D6R) in which Al moieties (including AlO₄ and AlO₅) and P moieties [including PO₄, PO₃(=O) and PO₂(=O) (OH)] are corner-shared through oxgens in an alternative manner. Compound 2 crystallizes in the monoclinic space group of C2/c (No. 15) with a=21.854(4), b=7.188(2), c=6.990(2) Å, β=103.77(2)°, V=1063.5(5) Å³ and Z=4. The structure is based on a new two-dimensionally connected inorganic network containing eight-membered rings in which AlO₄(OH₂)₂ and PO₂(OH)(=O) units are connected alternatively.