TY - JOUR A1 - Fahmy, A. A1 - Mix, Renate A1 - Schönhals, Andreas A1 - Friedrich, Jörg Florian T1 - Structure of plasma-deposited copolymer films prepared from acrylic acid and styrene: Part I dependence on the duty cycle N2 - Copolymers of acrylic acid and styrene (AA/S) were prepared by pulsed plasma deposition and their structures were studied in dependence on the duty cycle (DC) for a fixed composition of 1:1. As a result, low values of DC doses preserve the structure of monomers in the plasma deposited polymers while high DC leads to a higher degree of fragmentation and a loss in regular structure. Regarding plasma copolymerisation as a feasible method to finish surfaces with a definite number of functional groups it is necessary to characterize both, the chemical nature and the physical properties of the deposited layer. Therefore, a combination of different methods was employed for the characterization of thin plasma copolymer films (FTIR, dielectric spectroscopy, differential scanning calorimetry, X-ray photoelectron spectroscopy (XPS)). Special attention was paid on the unambiguous identification of COOH groups at the surface after derivatization with trifluoroethanol by XPS and in the volume by FTIR. The glass transition temperature of the copolymer system is lower than that for the both plasma deposited homopolymers and increases with the DC in difference to plasma deposited poly(acrylic acid). The dielectric measurements showed that the plasma deposited films were not thermally stable and underwent an undesired post-plasma chemical reaction. The results obtained by dielectric spectroscopy are discussed in detail in comparison with the data from FTIR and XPS measurements. KW - Plasmapolymerisation KW - Copolymerisation KW - Acrylic acid–styrene copolymer KW - Dynamic mobility KW - Plasma copolymerisation KW - Surface functionalization KW - Thin film properties PY - 2012 DO - https://doi.org/10.1002/ppap.201100117 SN - 1612-8850 SN - 1612-8869 VL - 9 IS - 3 SP - 273 EP - 284 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-25654 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mix, Renate A1 - Friedrich, Jörg Florian A1 - Inagaki, N. T1 - Modification of branched polyethylene by aerosol-assisted dielectric barrier discharge N2 - Three polyethylene (PE) types with different branching structures were subjected to air, water and ethanol aerosol-assisted dielectric barrier discharges (DBD) for surface modification. Using the air DBD the incorporated oxygen concentration was found to be independent on the branching of PE in contrast to the introduction of OH groups, which was PE-2 > PE-1 > PE-3. For water-aerosol DBD the succession of OH concentration was in the order of PE-1 > PE-2 > PE-3. Ethanol aerosol-assisted DBD produced the lowest concentration of OH groups also independent on the branching of PE. The chemical nature of introduced oxygen functional groups was inspected by X-ray photoelectron spectroscopy (XPS) and assigned as C–O, >C=O/CHO/O–C–O and O=C–O. KW - PE KW - Surface modification KW - Aerosol-assisted DBD PY - 2012 DO - https://doi.org/10.1002/ppap.201100052 SN - 1612-8850 SN - 1612-8869 VL - 9 IS - 4 SP - 406 EP - 416 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-25748 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mix, Renate A1 - Hielscher, Stefan A1 - Beck, Uwe A1 - Friedrich, Jörg Florian T1 - Plasma meets chemistry: Combined methods for tailored interface design in metal-polymer composites by selective chemical reactions on plasma modified surfaces N2 - The applicability of polymer-metal composites is mainly determined by the durability of the adhesive strength between both components. Aluminium (Al) deposited on polypropylene (PP) exemplifies different options of interface design. By deposition of plasma polymers on PP the effect of the type of the functionality was investigated. Spacer insertion was accomplished to position the functional group away from the topmost surface. A further kind of interface design involved a partial condensation of functional groups. Hydroxyl and carboxyl groups were most effective to improve adhesion in Al-PP systems. Approximately 7-10 carboxyl or 25-27 hydroxyl groups per 100 C atoms were necessary to increase the peel strength up to ~700 N/m. In this range, the failure of the composite propagated along the interface Al-tape (no peeling of the metal). Spacer molecules between surface and functional groups provoked the effect that the number of needed functional groups for maximum adhesion was strongly reduced. Linking of the functional groups resulted in non-peelable Al-PP laminates. Two adhesion tests were applied - the peel test and the centrifuge technology. For PP foils modified with chemically bonded and additionally linked silanol groups (no peeling) an adhesive strength of (2.5 ± 0.2) N/mm² was determined by centrifuge technology. XPS inspection of both fracture surfaces indicated a sub-surface failure in the polymer. T2 - HTPP-12 - 12th High-tech plasma processes conference CY - Bologna, Italy DA - 24.06.2012 KW - Adhesion PP-Al KW - Modified surfaces KW - Interface design PY - 2012 DO - https://doi.org/10.1088/1742-6596/406/1/012004 SN - 1742-6588 SN - 1742-6596 VL - 406 SP - 012004-1 - 012004-11 PB - IOP Publ. CY - Bristol, UK AN - OPUS4-28658 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Solomun, Tihomir A1 - Schimanski, A. A1 - Sturm, Heinz A1 - Mix, Renate A1 - Illenberger, E. T1 - Surface Modification of Polyamides by Direct Fluorination N2 - Bulk samples and thin films of polyamides (PA6 and PA12) were exposed to fluorine (1 - 10 vol.-% F2 in N2) and analysed with photoelectron (XPS) and infrared spectroscopy. Fluorination affects both, the amide and the hydrocarbon parts of the polymers. However, only the carbon atom next to the carbonyl is readily fluorinated. Chemical modification of the amide group is apparent in a large binding energy shift (+5 eV) of the N1s level and the appearance of a CO band at 1734 cm-1. It is concluded that the amide C-N bond is cleaved in the fluorination process and that COOH and NF2 end groups are formed. This conclusion is corroborated by the appearance of ester oxygen in the XPS and by the 19F NMR spectra of the volatile products that show fluorine signals chemically shifted about 200 ppm towards lower field as compared with the CHF environment. KW - Gasfluorierung KW - IR KW - XPS KW - AFM KW - NF2-Gruppe PY - 2004 UR - http://www.e-polymers.org SN - 1618-7229 IS - 8 SP - 1 EP - 16 PB - De Gruyter CY - [S.l.] AN - OPUS4-3425 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Solomun, Tihomir A1 - Mix, Renate A1 - Sturm, Heinz T1 - Immobilization of silanized DNA on glass: influence of the silane tether on the DNA hybridization N2 - Two trifunctional (trimethoxy and triethoxy) and one difunctional (methyldimethoxy) 3-mercaptopropyl-alkoxysilanes were covalently tethered to thiolated DNA oligonucleotides in solution. After deposition as microarrays onto glass, the immobilized DNA probes were tested for hybridization ability by a florescence-based method. The results demonstrate a large enhancement in the fluorescence signal when the functionality of the silane tether is reduced from three to two. An XPS analyses revealed that this is not due to a higher DNA surface density. FTIR spectra of the spin-coated silanes showed that the trifunctional silanes form branched and cyclic siloxane moieties, whereas the difunctional silane generates predominantly short straight siloxane chains. Therefore, the propensity of trifunctional silanes to form more complex networks leads to conformations of the bound DNA which are less favorable for the specific interaction with the complementary strand. The data implicate that further significant improvements in the DNA hybridization ability are possible by adroit choice of the silane system. KW - Silanized DNA KW - DNA immobilization KW - DNA hybridization KW - Fluorescence imaging KW - FTIRS KW - XPS PY - 2010 DO - https://doi.org/10.1021/am100263t SN - 1944-8244 SN - 0013-936X SN - 1944-8252 VL - 2 IS - 8 SP - 2171 EP - 2174 PB - ACS Publ. CY - Washington, DC, USA AN - OPUS4-22614 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Friedrich, Jörg Florian A1 - Mix, Renate A1 - Wettmarshausen, Sascha A1 - Sturm, Heinz ED - Tachibana, K. ED - Takai, O. T1 - A new concept of adhesion promotion in metal-polymer composites by introduction of covalently bonded hydrophobic spacers at interface T2 - Proceedings of the 18th International Symposium on Plasma Chemistry (ISPC-18) CY - Kyoto, Japan DA - 2007-08-26 PY - 2007 SN - 978-4-9903773-4-2 SP - 27A EP - p5, 1 PB - International Union of Pure and Applied Chemistry CY - Kyoto AN - OPUS4-20668 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -