TY - JOUR A1 - Friedrich, Jörg Florian A1 - Wettmarshausen, Sascha A1 - Meyer-Plath, Asmus A1 - Ziemann, Sylvia A1 - Hidde, Gundula A1 - Zeynalov, Eldar T1 - Plasmabromierung von graphitischen Materialien - Kovalente Anbindung organischer Moleküle N2 - Die hochselektive und ausbeutereiche plasmachemische Bromierung von Polyolefinoberflächen wurde auf graphitische Materialien übertragen. Oberflächen von graphenartigem Highly Oriented Pyrolytic Graphite (HOPG), natürlichem Graphit, mehrwandige Kohlenstoffnanoröhren (MWCNT) sowie Kohlenstoff-Fasern wurden im Bromdampfplasma behandelt. Während die Bromierung von Polyolefinoberflächen als radikalische Wasserstoffabstraktion mit nachfolgender Addition (Rekombination) oder durch nucleophile Substitution an sp³-hybridisierten C-Atomen abläuft, können graphitische Strukturen sowohl an sp³-hybridisierten Strukturdefekten als auch durch elektrophile Addition an vollständig C-substituierte aromatische Doppelbindungen bromiert werden. Dabei werden die planaren (graphitischen) sp²-C-Atome in die tetraedrische sp³-Hybridisierung umgewandelt und zu elektrisch nichtleitenden Strukturen gefaltet. Die maximalen Bromausbeuten bei Verwendung von Brom als Plasmamedium lagen je nach Substrat zwischen 10–50% Br/C, mit Bromoform deutlich darüber, was durch Kombinationen von Bromoform mit Brom oder Allylbromid mit Bromoform durch Schichtbildung auf über 70% Br/C gesteigert werden konnte. An die C-Br-Gruppen wurden nasschemisch verschiedene Amine nucleophil gepfropft. Die Pfropfausbeuten von 1–10 Moleküle je 100 C lagen deutlich niedriger als die erreichten Pfropfgrade von etwa 1–22 Moleküle je 100 C-Atome an Polyolefinoberflächen. Da nach der chemischen Pfropfung nahezu alle nichtgepfropften Br-Gruppen verschwunden waren, muss auf eine bevorzugte Rekonstruktion der planaren sp²-Graphitschicht geschlossen werden. KW - Polymerbromierung PY - 2012 U6 - https://doi.org/10.1002/vipr.201200481 SN - 0947-076X SN - 1522-2454 VL - 24 IS - 1 SP - 24 EP - 29 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-25518 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Friedrich, Jörg Florian A1 - Mix, Renate A1 - Schulze, Rolf-Dieter A1 - Meyer-Plath, Asmus A1 - Joshi, Ranjit A1 - Wettmarshausen, Sascha T1 - New Plasma Techniques for Polymer Surface Modification with Monotype Functional Groups N2 - The production of chemically-defined plasma polymers and the introduction of monotype functional groups onto polymer surfaces are described. One method is to lower the energetic level of low-pressure plasmas. Pressure- and plasma-pulsed plasmas were successfully tested for the production of chemically-defined plasma polymers by increasing the monomer supply during the plasma-off period. Well-defined ultra-thin polymer films with regular structure were deposited from atmospheric plasmas by electrospray techniques. Post-plasma wet-chemical processing was also applied, as were gas/liquid-based aerosols and underwater plasmas. KW - Plasma KW - Polymer-Oberflächenfunktionalisierung KW - Macromolecular plasma KW - Monotype functional groups KW - Plasma bromination KW - Plasma treatment KW - Pressure-pulsed plasma KW - Underwater plasma PY - 2008 U6 - https://doi.org/10.1002/ppap.200700145 SN - 1612-8850 SN - 1612-8869 VL - 5 IS - 5 SP - 407 EP - 423 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-17742 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Wettmarshausen, Sascha A1 - Mix, Renate A1 - Meyer-Plath, Asmus A1 - Mittmann, Hans-Ulrich A1 - Friedrich, Jörg Florian ED - K.L. Mittal, T1 - Plasma Bromination - a selective way to monotype functionalized polymer surfaces KW - Functional groups KW - Polymer surfaces KW - Plasma bromination KW - Grafting KW - Spacer KW - Selective plasma process PY - 2009 SN - 978-90-04-16590-8 VL - 5 SP - 3 EP - 18 PB - Koninklijke Brill NV CY - Leiden, The Netherlands AN - OPUS4-18944 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Friedrich, Jörg Florian A1 - Wettmarshausen, Sascha A1 - Hanelt, Sven A1 - Mach, Reinhard A1 - Mix, Renate A1 - Zeynalov, Eldar A1 - Meyer-Plath, Asmus T1 - Plasma-chemical bromination of graphitic materials and its use for subsequent functionalization and grafting of organic molecules N2 - Plasma-chemical bromination has been shown to be well-suited for highly selective and efficient C–Br-functionalization of polyolefin surfaces and has now been applied to graphitic materials, including highly oriented pyrolytic graphite (HOPG), natural graphite, carbon nanotubes, and graphitized carbon fibres. In contrast to the radical substitution of hydrogen by bromine at hydrogen-terminated sp3-hybridized carbon, bromination of all-carbon bound sp2-hybridized carbon in graphene requires addition to aromatic double bonds. The related change of sp2 to sp3 hybridization of the carbon atoms involved helps to explain experimental results of a loss in surface planarity on brominated HOPG. Bromine concentrations of up to 50 bromine atoms per 100 C-atoms were achieved in elemental bromine vapour under low-pressure plasma conditions using low-energetic inductively coupled radio-frequency plasma excitation. The time scale of the bromination progress was found to increase with the specific surface area of the material. The results of plasma-chemical bromination are compared to that of wet-chemical electrophilic addition reactions, which achieved 28 Br per 100 C for MWCNT. The resulting C–Br bonds from plasma-chemical processing of graphitic materials were shown to be well-suited for hydroxyl functionalization and for grafting of organic molecules by nucleophilic substitution with 1,6-diaminohexane and (3-aminopropyl)triethoxysilane. PY - 2010 U6 - https://doi.org/10.1016/j.carbon.2010.06.054 SN - 0008-6223 SN - 1873-3891 VL - 48 IS - 13 SP - 3884 EP - 3894 PB - Pergamon Press CY - New York, NY AN - OPUS4-21954 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wettmarshausen, Sascha A1 - Friedrich, Jörg Florian A1 - Meyer-Plath, Asmus A1 - Kalinka, Gerhard A1 - Hidde, Gundula A1 - Weidner, Steffen T1 - Coating of carbon fibers with adhesion-promoting thin poly(acrylic acid) and poly(hydroxyethylmethacrylate) layers using electrospray ionization N2 - Thin coatings of poly(acrylic acid) (PAA) and poly(hydroxyethylmethacrylate) (PHEMA) were deposited onto carbon fibers by means of the electrospray ionization (ESI) technique in ambient air. These high-molecular weight polymer layers were used as adhesion promoters in carbon fiber–epoxy resin composites. Within the ESI process, the carbon fibers were completely enwrapped with polymer in the upper 10 plies of a carbon fiber roving. As identified with scanning electron microscopy also shadowed fibers in a bundle as well as backsides of fiber rovings were pinhole-free coated with polymers (‘electrophoretic effect'). Under the conditions used, the layers have a granular structure. Residual solvent was absent in the deposit. PAA and PHEMA films did not show any changes in composition and structure in comparison with the original polymers as analyzed by X-ray photo-electron spectroscopy and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Single-fiber pullout tests of coated fibers embedded in epoxy resin showed significantly increased interfacial shear strength. It is assumed that chemical bonds between carbon fiber poly(acrylic acid) and epoxy resin contribute significantly to the improved interactions. KW - Adhesion promotion KW - Thin polymer layers KW - Electrospray ionization (ESI) KW - Carbon fiber–epoxy resin laminates KW - Layer topography PY - 2015 U6 - https://doi.org/10.1080/01694243.2015.1040980 SN - 0169-4243 SN - 1568-5616 VL - 29 IS - 15 SP - 1628 EP - 1650 PB - VNU Science Press CY - Utrecht AN - OPUS4-34564 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -