TY - JOUR A1 - Ünveren, Ercan A1 - Kemnitz, E. A1 - Oran, Umut A1 - Unger, Wolfgang T1 - Static TOF-SIMS Surface Analysis of a CCl2F2 Activated Chromia Catalyst Used for a Cl/F Exchange Reaction N2 - Static TOF-SIMS results strongly underpin earlier conclusions from ESCA, XANES, and tracer studies that the accumulation of fluorine and chlorine at the surface of chromia by a heterogeneous reaction with a chlorofluorocarbon compound results in the formation of mixed chromium oxide halide species and not in the nucleation of CrCl3 and/or CrF3 phases. KW - Oberflächenanalytik KW - Katalyse PY - 2004 DO - https://doi.org/10.1021/jp046773h SN - 1520-6106 SN - 1520-5207 SN - 1089-5647 VL - 108 SP - 15454 EP - 15456 PB - Soc. CY - Washington, DC AN - OPUS4-4718 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Oran, Umut A1 - Swaraj, Sufal A1 - Friedrich, Jörg Florian A1 - Unger, Wolfgang T1 - Surface analysis of plasma-deposited polymer films, 1: Time of Flight Static Secondary Ion Mass Spectrometry (ToF-SSIMS) of plasma polystyrene before and after exposure to ambient air N2 - Pulsed plasma-deposited polystyrene films were studied by time-of-flight static secondary ion mass spectrometry (ToF-SSIMS) before and after exposure to ambient air. The influence of the external plasma parameters on the secondary ion mass spectra of plasma-deposited polystyrene films was investigated. From these data, information on the chemical character of the plasma polystyrene films was derived. In the range of deposition conditions applied in this study, the fragmentation of styrene is a minor process. The main process is probably the radical chain propagation to polymers. All the polystyrene plasma polymers, relying on ToF-SIMS, seem to be rather similar to a reference polystyrene oligomer sample. When the plasma polymers are exposed to air, extensive oxygen incorporation occurs. Oxygen uptake was found to alter the emission probabilities of secondary ions. A relation between the regularity of the plasma polymers and the amount of oxygen incorporation was found. The result was that the chemical regularity of the plasma polystyrene decreases when the effective power in the plasma is increased. PY - 2004 DO - https://doi.org/10.1002/ppap.200400002 SN - 1612-8850 SN - 1612-8869 VL - 1 SP - 123 EP - 133 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-4697 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Oran, Umut T1 - Surface analysis of plasma-deposited polymer films by Time of Flight Static Secondary Ion Mass Spectrometry (ToF-SSIMS) before and after exposure to ambient air T2 - 9th Conference on Plasma Surface Engineering CY - Garmisch-Partenkirchen, Germany DA - 2004-09-13 PY - 2004 AN - OPUS4-6440 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Swaraj, Sufal A1 - Oran, Umut A1 - Lippitz, Andreas A1 - Schulze, Rolf-Dieter A1 - Friedrich, Jörg Florian A1 - Unger, Wolfgang T1 - Surface Analysis of Plasma-Deposited Polymer Films, 2: Analysis of Post-Plasma Air Reacted Plasma Polymerized Styrene by X-Ray Photoelectron Spectroscopy and X-Ray Absorption Spectroscopy N2 - Chemical properties of plasma-polymerized styrene films can be effectively controlled by the appropriate choice of external plasma parameters, such as duty cycle, power and monomer pressure. Chemical properties here are the regularity of the primary structure, the amount of long living radicals and branching or cross-linking or both in plasma polymerized styrene films, which can be indirectly monitored by X-ray photoelectron spectroscopy (XPS) and near edge X-ray absorption fine structure (NEXAFS) spectroscopy. Principally, XPS and NEXAFS spectra of plasma-polymerized styrene show all the spectroscopic fingerprints characteristic of atactic polystyrene indicating an inherent similarity of the respective primary chemical structures. There is an increase in irregularity and radical concentration for the plasma deposited films with increasing duty cycle or power. With an increase in monomer pressure, a decreased level of monomer fragmentation and, consequently, an increase in regularity must be concluded from the experimental data. The applied power regulates the fragmentation of the monomers as monitored by spectroscopic signals correlated to the aromatic rings. A trend in the extent of the post-plasma oxygen incorporation according to the variation of the various external plasma parameters was deduced, which agrees with earlier ToF-SIMS findings KW - Chemical characterization KW - ESCA/XPS KW - NEXAFS KW - Plasma polymerization KW - Polystyrene PY - 2004 DO - https://doi.org/10.1002/ppap.200400022 SN - 1612-8850 SN - 1612-8869 VL - 1 SP - 134 EP - 140 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-6935 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Oran, Umut A1 - Swaraj, Sufal A1 - Friedrich, Jörg Florian A1 - Unger, Wolfgang T1 - Surface Analysis of Plasma-Deposited Polymer Films, 3: In situ Characterization of Plasma-Deposited Ethylene Films by ToF-SSIMS N2 - Pulsed-plasma-deposited ethylene films were studied by time-of-flight static secondary ion mass spectrometry (ToF-SSIMS) before and after exposure to ambient air. The influence of the external plasma parameters on the secondary ion mass spectra of plasma-deposited ethylene films was investigated. From these data, information on the chemical character of the plasma-deposited ethylene films was derived. The investigation of the effect of external plasma parameters on the chemical character of the plasma-deposited ethylene films revealed that there were some drastic changes in the secondary ion mass spectra of the films. It was found that fragmentation and re-arrangement of the monomer molecules in the plasma, which affects the chemical character of the deposited films, vary according to the external plasma parameters. When the plasma polymers are exposed to air, extensive oxygen incorporation occurs. The oxygen uptake is high at the beginning and then it levels of. Some indications for the formation and decay of peroxy radicals (COO) and, subsequently, hydroperoxides (COOH) are found. It was observed that the oxygen uptake of the plasma deposited ethylene films increase when the plasma conditions become harder. KW - Ageing KW - Plasma polymerization KW - Polyethylene (PE) KW - ToF-SIMS PY - 2004 DO - https://doi.org/10.1002/ppap.200400025 SN - 1612-8850 SN - 1612-8869 VL - 1 SP - 141 EP - 152 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-6936 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Unger, Wolfgang A1 - Swaraj, Sufal A1 - Oran, Umut A1 - Lippitz, Andreas A1 - Schulze, Rolf-Dieter T1 - NEXAFS - spectroscopy on plasma-polymerized films prepared from organic molecules (ethylene, allyl alcohol, styrene) KW - Plasma KW - Beschichtung KW - Organische Filme KW - Röntgenabsorptionsspektroskopie PY - 2004 UR - http://www.helmholtz-berlin.de/media/media/oea/web/pr_webseite/druckschriften/berichte/bessy/annualreport2003.pdf#page=297 SN - 0179-4159 SP - 297 EP - 299 PB - Berliner Elektronenspeicherring-Gesellschaft für Synchrotronstrahlung CY - Berlin AN - OPUS4-3478 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Oran, Umut A1 - Ünveren, Ercan A1 - Wirth, Thomas A1 - Unger, Wolfgang T1 - Poly-dimethyl-siloxane (PDMS) contamination of polystyrene (PS) oligomers samples: a comparison of time-of-flight static secondary ion mass spectrometry (TOF-SSIMS) and X-ray photoelectron spectroscopy (XPS) results N2 - Pure and PDMS contaminated PS oligomers films were investigated both by time-of-flight static secondary ion mass spectrometry (TOF-SSIMS) and X-ray photoelectron spectroscopy (XPS). The secondary ion spectra from the PDMS contaminated PS oligomers were almost completely related to PDMS. XPS revealed a PDMS contamination characterized by a silicon surface concentration of 6 at.%. Obviously siloxane contaminants existing on the surface of a silicon wafer may diffuse towards the PS oligomers outermost surface resulting in a rather high PDMS surface concentration of about 85%. Due to the known differences in the information depth and sensitivity of SSIMS and XPS very different detection limits are to be considered. In elimination of siloxane contaminants by ultrasonication in hexane was found to be an effective way. Another common organic cleaning procedure, which is ultrasonication in trichloroethylene (TCE), subsequently in isopropanol and finally in acetone was found to be ineffective for cleaning of PDMS contaminated silicon wafers. KW - PDMS KW - TOF-SIMS KW - Polystyrene KW - Segregation PY - 2004 DO - https://doi.org/10.1016/j.apsusc.2003.12.008 SN - 0169-4332 SN - 1873-5584 VL - 227 SP - 318 EP - 324 PB - North-Holland CY - Amsterdam AN - OPUS4-3479 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -