TY - JOUR A1 - Baytekin, H. Tarik A1 - Wirth, Thomas A1 - Gross, Thomas A1 - Sahre, Mario A1 - Unger, Wolfgang A1 - Theisen, J. A1 - Schmidt, M. T1 - Surface analytical characterization of micro-fluidic devices hot embossed in polymer wafers: Surface chemistry and wettability N2 - Recently, time-of-flight secondary ion mass spectrometry (ToF-SIMS) and X-ray photoelectron spectroscopy (XPS) instrumentation has been used to address areas of interest within micro-fluidic devices providing full access to the surface chemistry established at the bottom of micro-channels therein. After careful calibration, information on surface chemistry as obtained by ToF-SIMS or XPS can be interpreted in terms of wettability expressed as contact angles which are then characteristic for the inner walls of micro-channels. Standard contact angle measurement is not applicable in micro-channels. The approach has been demonstrated to be successful with two different micro-fluidic devices hot embossed into high-end quality poly(methyl methacrylate) (PMMA) or Polycarbonate wafers. A pre-selected surface chemistry at micro-channel walls can be established by plasma technologies but ageing and rinsing effects have to be under control. A combination of ToF-SIMS, XPS and contact angle measurement techniques has been demonstrated to provide the required information. Finally, it is shown by ToF-SIMS and XPS analysis that in the production of micro-fluidic parts during practical processing using hot embossing technologies, material originating from cover foils will reside on the polymer wafer's surface. Moreover, residues of releasing agents as silicone oil used during processing can be detected by ToF-SIMS. Both cover foil residues and silicones are issues of trouble shooting in micro-fluidics because they will change contact angles efficiently. KW - Micro-fluidic device KW - PMMA KW - Polycarbonate KW - Plasma treatment KW - Wettability KW - ToF-SIMS KW - XPS PY - 2010 DO - https://doi.org/10.1002/sia.3149 SN - 0142-2421 SN - 1096-9918 VL - 42 IS - 8 SP - 1417 EP - 1431 PB - Wiley CY - Chichester AN - OPUS4-21712 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Baytekin, H.T. A1 - Wirth, Thomas A1 - Gross, Thomas A1 - Treu, Dieter A1 - Sahre, Mario A1 - Theisen, J. A1 - Schmidt, M. A1 - Unger, Wolfgang T1 - Determination of wettability of surface-modified hot-embossed polycarbonate wafers used in microfluidic device fabrication via XPS and ToF-SIMS N2 - The wettability of the surfaces inside the microchannels of a microfluidic device is an important property considering a liquid flows through them. Contact angle measurements usually applied to test the wettability of surfaces cannot be used for an analysis of microchannel walls within microfluidic devices. A workaround is the use of surface analytical methods, which are able to reach points of interest in microchannels and may provide information on the surface chemistry established there. In calibrating these methods by using flat polymer wafers, where the contact angle can be measured as usual, data measured in real microchannels can be evaluated in terms of wetting properties. Reference wafers of bisphenol-A polycarbonate, a polymeric material that is often used in fluidic microdevice fabrication, were treated under different oxygen plasma conditions. The modified surfaces were characterized by using XPS, time of flight (ToF)-SIMS and atomic force microscope (AFM). Surface chemistry and surface topography have been correlated with contact angle measurements. In addition, effects of ageing or rinsing after plasma treatment have also been investigated. KW - Oxygen plasma KW - Polycarbonate KW - XPS KW - ToF-SIMS KW - Principal component analysis PY - 2008 DO - https://doi.org/10.1002/sia.2724 SN - 0142-2421 SN - 1096-9918 VL - 40 IS - 3-4 SP - 358 EP - 363 PB - Wiley CY - Chichester AN - OPUS4-17340 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dietrich, Paul A1 - Horlacher, T. A1 - Girard-Lauriault, Pierre-Luc A1 - Gross, Thomas A1 - Lippitz, Andreas A1 - Min, Hyegeun A1 - Wirth, Thomas A1 - Castelli, R. A1 - Seeberger, P. H. A1 - Unger, Wolfgang T1 - Adlayers of dimannoside thiols on gold: surface chemical analysis N2 - Carbohydrate films on gold based on dimannoside thiols (DMT) were prepared, and a complementary surface chemical analysis was performed in detail by X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS), near-edge X-ray absorption fine structure (NEXAFS), FT-IR, and contact angle measurements in order to verify formation of ω-carbohydrate-functionalized alkylthiol films. XPS (C 1s, O 1s, and S 2p) reveals information on carbohydrate specific alkoxy (C–O) and acetal moieties (O–C–O) as well as thiolate species attached to gold. Angle-resolved synchrotron XPS was used for chemical speciation at ultimate surface sensitivity. Angle-resolved XPS analysis suggests the presence of an excess top layer composed of unbound sulfur components combined with alkyl moieties. Further support for DMT attachment on Au is given by ToF-SIMS and FT-IR analysis. Carbon and oxygen K-edge NEXAFS spectra were interpreted by applying the building block model supported by comparison to data of 1-undecanethiol, poly(vinyl alcohol), and polyoxymethylene. No linear dichroism effect was observed in the angle-resolved C K-edge NEXAFS. KW - Carbohydrates KW - Self-assembled monolayer KW - XPS KW - NEXAFS KW - ToF-SIMS KW - Surface chemical analysis PY - 2011 DO - https://doi.org/10.1021/la104038q SN - 0743-7463 SN - 1520-5827 VL - 27 IS - 8 SP - 4808 EP - 4815 PB - American Chemical Society CY - Washington, DC AN - OPUS4-23554 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weigel, W. A1 - Unger, Wolfgang A1 - Graf, Nora A1 - Gross, Thomas A1 - Wirth, Thomas T1 - Surface Chemical Analysis of DNA Microarrays - Application of XPS and ToF-SIMS for Surface Chemical Imaging on the µm Scale KW - Microarrays KW - Oberflächenanalytik KW - XPS KW - ToF-SIMS KW - Chemical imaging PY - 2008 SN - 1611-597X VL - 12 IS - 10 SP - 14 EP - 16 PB - GIT-Verlag CY - Darmstadt AN - OPUS4-18307 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Graf, Nora A1 - Gross, Thomas A1 - Wirth, Thomas A1 - Weigel, W. A1 - Unger, Wolfgang T1 - Application of XPS and ToF-SIMS for surface chemical analysis of DNA microarrays and their substrates N2 - The chemical composition of the functional surfaces of substrates used for microarrays is one of the important parameters that determine the quality of a microarray experiment. In addition to the commonly used contact angle measurements to determine the wettability of functionalized supports, X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) are more specific methods to elucidate details about the chemical surface constitution. XPS yields information about the atomic composition of the surface, whereas from ToF-SIMS, information on the molecular species on the surface can be concluded. Applied on printed DNA microarrays, both techniques provide impressive chemical images down to the micrometer scale and can be utilized for label-free spot detection and characterization. Detailed information about the chemical constitution of single spots of microarrays can be obtained by high-resolution XPS imaging. KW - Microarrays KW - Surface analysis KW - XPS KW - ToF-SIMS KW - Chemical imaging PY - 2009 DO - https://doi.org/10.1007/s00216-009-2599-x SN - 1618-2642 SN - 1618-2650 VL - 393 IS - 8 SP - 1907 EP - 1912 PB - Springer CY - Berlin AN - OPUS4-19245 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hinze, A. A1 - Klages, C.-P. A1 - Zänker, A. A1 - Thomas, M. A1 - Wirth, Thomas A1 - Unger, Wolfgang T1 - ToF-SIMS imaging of DBD-plasma-printed microspots on BOPP substrates N2 - Imaging ToF-SIMS has been applied to characterize the surface chemistry variations across small areas produced by a DBD-type plasma printing technique on a BOPP substrate using pure nitrogen and a nitrogen-hydrogen gas mixture. CH4N+ and CNO- secondary ions are detected with high yields remote from the discharge region. They are discussed to be due to surface modifications of the substrate by metastable gas-phase species. On the other hand, surface species exist that are preferentially formed by reactions of the substrate with short-lived species which are only present close to the plasma discharge region. A C3H8O+ secondary fragment ion is assumed to be a key fragment of such a surface species. KW - ToF-SIMS KW - Plasma KW - Polymer KW - Dielectric barrier discharges (DBD) KW - Plasma printing KW - Polymer modification KW - Surface modification KW - Time-of-flight secondary-ion mass spectroscopy (ToF-SIMS) imaging PY - 2008 DO - https://doi.org/10.1002/ppap.200700138 SN - 1612-8850 SN - 1612-8869 VL - 5 IS - 5 SP - 460 EP - 470 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-19342 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dietrich, Paul A1 - Horlacher, T. A1 - Girard-Lauriault, Pierre-Luc A1 - Gross, Thomas A1 - Lippitz, Andreas A1 - Min, Hyegeun A1 - Wirth, Thomas A1 - Castelli, R. A1 - Seeberger, P. A1 - Unger, Wolfgang T1 - Multimethod chemical characterization of carbohydrate-functionalized surfaces N2 - A combined XPS, NEXAFS, and ToF-SIMS chemical surface characterization of carbohydrate-functionalized gold and glass surfaces is presented. Spot shape and chemical composition across a spot surface are provided by surface-sensitive methods as ToF-SIMS and XPS, used in their imaging modes. Moreover, the feasibility of this multimethod approach to control relevant production steps of a carbohydrate microarray prototype is demonstrated. KW - Carbohydrates KW - Microarrays KW - Self-assembled monolayers KW - XPS KW - NEXAFS KW - ToF-SIMS PY - 2011 DO - https://doi.org/10.1080/07328303.2011.615181 SN - 0732-8303 VL - 30 IS - 4-6 SP - 361 EP - 372 PB - Taylor & Francis CY - London [u.a.] AN - OPUS4-24874 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Girard-Lauriault, P.-L. A1 - Dietrich, Paul A1 - Gross, Thomas A1 - Wirth, Thomas A1 - Unger, Wolfgang T1 - Chemical characterization of the long-term ageing of nitrogen-rich plasma polymer films under various ambient conditions N2 - Nitrogen rich plasma polymer films (L-PPE:N) were prepared by low-pressure RF plasma using a 1:1 mixture of ethylene and ammonia and aged for 345 d in four different ambient conditions: (i) at room temperature (RT) in air; (ii) at RT in nitrogen; (iii) at -20?°C in air and; (iv) at –20 °C in nitrogen. The films were analyzed by X-ray photoelectron spectroscopy (XPS) and by time-of-flight secondary ion mass spectrometry (ToF-SIMS) at various intervals over the duration of the experiment. The ageing of primary amines, NH2, was followed by chemical derivatization with 4-trifluoromethyl benzaldehyde. Storage at –20 °C, mostly independently of ambient atmosphere, slowed down ageing to almost undetectable levels as evaluated by the analytical methods used for this study. KW - Ageing KW - Plasma polymers KW - Primary amines KW - ToF-SIMS KW - XPS PY - 2013 DO - https://doi.org/10.1002/ppap.201200118 SN - 1612-8850 SN - 1612-8869 VL - 10 IS - 4 SP - 388 EP - 395 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-28006 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Beck, Uwe A1 - Fritz, Thomas A1 - Gamer, Nadja A1 - Wirth, Thomas T1 - VAMAS - Versailles Project on Advanced Materials and Standards N2 - Glühentladung optischer Ausstrahlungsspektroskopie (GDOES) wurde ursprünglich für die elementare Analyse von Größenmaterialien entwickelt. Mehrere Gruppen führten diese Methode zur Analyse von Anstrichen, Laienstapeln und dünnen Filmen durch. In den frühen Neunzigern wurde eine ISO-TC 201-Arbeitsgruppe gegründet, um Normen für alle Formen der Glühentladungsspektroskopie (GDS) zu entwickeln und die Fähigkeiten der Oberflächenchemikalien-Analyse zu beurteilen, insbesondere für die Tiefe von gestuften Systemen. Die Quantifizierung von Tiefenprofilen, d.h. die Umwandlung von Intensitäts-Zeit- Profilen in Konzentrierungs-Tiefen-Profile ist für dc-mode entwickelt worden. 1997 wurde ein VAMAS TWA 2 Vorschlag für ein Referenzanstrich für GD-OES Tiefe gemacht. Entsprechend dem VAMAS Beurteilungsverfahren wurde dieser Vorschlag 1998 mit einigen geringfügigen Änderungen genehmigt. T3 - BAM Forschungsberichtreihe - 242 PY - 2001 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-2083 SN - 978-3-89701-713-X SN - 0938-5533 VL - 242 SP - 1 EP - 64 PB - Wirtschaftsverlag NW CY - Bremerhaven AN - OPUS4-208 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sobol, Oded A1 - Böllinghaus, Thomas A1 - Wirth, Thomas A1 - Unger, Wolfgang A1 - Eliezer, D. T1 - High resolution ToF-SIMS imaging of deuterium permeation and cracking in duplex stainless steels N2 - Fundamental understanding and elucidation of hydrogen assisted degradation and trapping mechanisms is dependent on sufficient imaging techniques for respective hydrogen interactions, in particular with multi-phase metallic microstructures. The present work shows the progress in elucidating the deuterium behavior in austenitic-ferritic duplex stainless steels under the consideration that deuterium behaves in many ways similarly to hydrogen. A novel combination of deuterium permeation and in-situ Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) imaging technique is compared with post charging ToF-SIMS imaging experiments. As a step beyond state-of-the-art, integration of chemo-metric and high resolution structural characterization techniques with computational multivariate data analysis (MVA) and data fusion is presented. T2 - 2016 International Hydrogen Conference CY - Grand Teton National Park, Jackson Lake Lodge, Wyoming, USA DA - 11.09.2016 KW - DSS KW - ToF-SIMS KW - Data-fusion KW - EBSD PY - 2017 SN - 978-0-7918-6138-7 SP - 407 EP - 415 PB - ASME Press CY - Two Park Ave. New-York, NY 10016, USA AN - OPUS4-42647 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Holzweber, Markus A1 - Sobol, Oded A1 - Wirth, Thomas A1 - Böllinghaus, Thomas A1 - Unger, Wolfgang T1 - Deuterium permeation and cracking in duplex steels as viewed by ToF-SIMS and HR-SEM with data fusion N2 - Better understanding of hydrogen assisted degradation and trapping mecha-nisms requires sufficient imaging techniques for respective hydrogen-microstructure interaction studies, in particular with multi-phase metallic micro-structures [1]. The present work is focusing on the elucidation of deuterium be-havior in two austenitic-ferritic duplex stainless steels (DSS) under the assumption that deuterium behaves in many ways similarly to hydrogen [2]. For case studies standard 2205 and lean 2101 DSSs were chosen due to the extensive use of these steels in industry [3]. The analyses were conducted by using a novel in-situ permeation and Time-of-Flight secondary ion mass spectrometry (ToF-SIMS) imaging technique or by ex-situ ToF-SIMS imaging following electrochemical charging experiments. Another pioneering procedure was data fusion (including chemometry) of results of powerful laterally resolved chemical analysis and high resolution structural characterization techniques . Results for the ex-situ observations showed a different influence of deuterium loading on the two steel grades as well as different damage mechanisms in each phase. Formation of sub-surface blisters between the ferrite and austenite were obtained in both the standard and the lean DSS. In both steels, an increased deuterium concentration was observed around deformed regions such as cracks, confirming that they originate from the presence of deuterium [4]. The formation of parallel cracks was obtained only in the austenite within the standard duplex whereas in the lean duplex the highest intensity of deuterium was obtained in the austenite along the ferrite-austenite interphase. In comparison, application of the novel in-situ permeation technique enabled to register and record the deuterium permeation through the material and the respective saturation sequence of the two phases as well as the interfaces. Faster diffusion of the deuterium was observed in the ferrite and a direct proof for deuterium enrichment at the austenite-ferrite interface has been given [1]. The integration of the specified techniques gives a better insight into the processes leading to hydrogen induced failure. These two experimental techniques provide very valuable tools for elucidation of respective metallurgical failure mechanisms that can be used for the validation of respective numerical models for hydrogen assisted cracking (HAC). T2 - 19. Arbeitstagung Angewandte Oberflächenanalytik CY - Soest, Germany DA - 05.09.2016 KW - ToF-SIMS KW - Hydrogen assisted cracking KW - Data fusion KW - SEM PY - 2016 AN - OPUS4-37484 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Straub, Franka A1 - Wirth, Thomas A1 - Hertwig, Andreas A1 - Hodoroaba, Vasile-Dan A1 - Unger, Wolfgang A1 - Böllinghaus, Thomas T1 - Imaging the microstructure of duplex stainless steel samples with TOF-SIMS N2 - Time-of-flight secondary ion mass spectrometry (TOF-SIMS) mappings provide a visualization of the distribution of chemical elements and phases on polished duplex steel surfaces as element and fragment secondary ion signals. The advantage of TOF-SIMS, compared to optical microscopy, is its potential to analyze the chemical composition with a lateral resolution at a submicrometer scale. TOF-SIMS mappings allow distinguishing between ferritic and austenitic phases because of the phase selective detection method without any requirement of etching or other processing. KW - TOF-SIMS mappings KW - Duplex stainless steel KW - Surface analysis KW - Ferritic phase KW - Austenitic phase PY - 2010 UR - http://onlinelibrary.wiley.com/doi/10.1002/sia.3385/pdf DO - https://doi.org/10.1002/sia.3385 SN - 0142-2421 SN - 1096-9918 VL - 42 IS - 6-7 SP - 739 EP - 742 PB - Wiley CY - Chichester AN - OPUS4-21818 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -