TY - JOUR A1 - Rades, Steffi A1 - Hodoroaba, Vasile-Dan A1 - Salge, T. A1 - Wirth, Thomas A1 - Lobera, M.P. A1 - Labrador, R.H. A1 - Natte, Kishore A1 - Behnke, Thomas A1 - Gross, Thomas A1 - Unger, Wolfgang T1 - High-resolution imaging with SEM/T-SEM, EDX and SAM as a combined methodical approach for morphological and elemental analyses of single engineered nanoparticles N2 - The combination of complementary characterization techniques such as SEM (Scanning Electron Microscopy), T-SEM (Scanning Electron Microscopy in Transmission Mode), EDX (Energy Dispersive X-ray Spectroscopy) and SAM (Scanning Auger Microscopy) has been proven to be a powerful and relatively quick characterization strategy for comprehensive morphological and chemical characterization of individual silica and titania nanoparticles. The selected “real life” test materials, silica and titania, are listed in the OECD guidance manual as representative examples because they are often used as commercial nanomaterials. Imaging by high resolution SEM and in the transmission mode by T-SEM allows almost simultaneous surface and in-depth inspection of the same particle using the same instrument. EDX and SAM enable the chemical characterization of bulk and surface of individual nanoparticles. The core–shell properties of silica based materials are addressed as well. Titania nominally coated by silane purchased from an industrial source has been found to be inhomogeneous in terms of chemical composition. KW - surface and in-depth inspection KW - silica nanoparticles KW - titania nanoparticles PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-316296 DO - https://doi.org/10.1039/c4ra05092d SN - 2046-2069 VL - 4 IS - 91 SP - 49577 EP - 49587 PB - RSC Publishing CY - London AN - OPUS4-31629 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 - 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 - JOUR A1 - Kim, K.J. A1 - Unger, Wolfgang A1 - Kim, J.W. A1 - Moon, D.W. A1 - Gross, Thomas A1 - Hodoroaba, Vasile-Dan A1 - Schmidt, Dieter A1 - Wirth, Thomas A1 - Jordaan, W. A1 - van Staden, M. A1 - Prins, S. A1 - Zhang, L. A1 - Fujimoto, T. A1 - Song, X.P. A1 - Wang, H. T1 - Inter-laboratory comparison: quantitative surface analysis of thin Fe-Ni alloy films N2 - An international interlaboratory comparison of the measurement capabilities of four National Metrology Institutes (NMIs) and one Designated Institute (DI) in the determination of the chemical composition of thin Fe-Ni alloy films was conducted via a key comparison (K-67) of the Surface Analysis Working Group of the Consultative Committee for Amount of Substance. This comparison was made using XPS (four laboratories) and AES (one laboratory) measurements. The uncertainty budget of the measured chemical composition of a thin alloy film was dominated by the uncertainty of the certified composition of a reference specimen which had been determined by inductively coupled plasma mass spectrometry using the isotope dilution method. Pilot study P-98 showed that the quantification using relative sensitivity factors (RSFs) of Fe and Ni derived from an alloy reference sample results in much more accurate result in comparison to an approach using RSFs derived from pure Fe and Ni films. The individual expanded uncertainties of the participants in the K-67 comparison were found to be between 2.88 and 3.40 atomic %. The uncertainty of the key comparison reference value (KCRV) calculated from individual standard deviations and a coverage factor (k) of 2 was 1.23 atomic %. KW - Quantification KW - Fe-Ni alloy KW - Uncertainty KW - Key comparison KW - Traceability PY - 2012 DO - https://doi.org/10.1002/sia.3795 SN - 0142-2421 SN - 1096-9918 VL - 44 IS - 2 SP - 192 EP - 199 PB - Wiley CY - Chichester AN - OPUS4-24505 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 - 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 - 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 - 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 - 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 - 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 -