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 DO - 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 - JOUR A1 - Joshi, Ranjit A1 - Friedrich, Jörg Florian A1 - Wagner, M. T1 - Role of hydrogen peroxide in selective OH group functionalization of polypropylene surfaces using underwater capillary discharge N2 - Plasma chemical methods are well suited for introducing functional groups to the surfaces of chemically inert polymers such as polyolefins. However, a broad variety of functional groups are often formed. Unfortunately, for further chemical processing such as grafting of molecules for advanced applications a highly dense monotype functionalized polyolefin surface is needed. Therefore, the main task was to develop a selective surface functionalization process, which formed preferably only a single type of functional groups at the surface in high concentration. Amongst the novel plasma methods, the underwater plasma process (UWP) is one of most attractive options to solve the problem of monotype functionalization. Such plasma is an efficient source of ions, electrons, UV-radiation, high-frequency shock waves, radicals such as hydroxyl radical, and reactive neutral molecules such as hydrogen peroxide. In contrast to established gas phase glow discharge processes, the water phase limits the particle and radiation energies and thus the energy input into the polymer. By virtue of the liquid water environment, which moderates highly energetic plasma species, extensive oxidation, degradation, cross-linking and radical formation on the polymer are more limited as compared to gas plasma exposure. The variety of plasma produced species in the water phase is also much smaller because of the limited reaction possibilities of the plasma with water. The possibility to admix a broad variety of chemical additives makes underwater plasma even more attractive. Hydrogen peroxide and the catalyst (Fe-ZSM5) should influence and increase the equilibrium concentration of OH radicals in the underwater plasma process. It was found that these radicals played a very important role in OH functionalization of polyolefin surfaces. Hydrogen peroxide was identified to be the most prominent precursor for OH group formation in the UWP. The catalyst would affect the steady state of OH radical formation and its reaction with the substrate surface and thus accelerates the functionalization process. KW - Surface modification KW - Polymer functionalization KW - Underwater plasma KW - Capillary discharge KW - Hydroxyl functionalization KW - Hydrogen peroxide KW - Hydroperoxyl radicals KW - Heterogeneous catalysis KW - Fenton-like processes PY - 2011 DO - https://doi.org/10.1163/016942410X520862 SN - 0169-4243 SN - 1568-5616 VL - 25 SP - 283 EP - 305 PB - VNU Science Press CY - Utrecht AN - OPUS4-22413 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Joshi, Ranjit A1 - Schulze, Rolf-Dieter A1 - Meyer-Plath, Asmus A1 - Wagner, M.H. A1 - Friedrich, Jörg Florian T1 - Selective surface modification of polypropylene using underwater plasma technique or underwater capillary discharge N2 - Among new types of plasma processes, the underwater plasma is one of the most attractive methods for functionalization of polymer surfaces. The interesting features of plasma solution system are that the material surfaces to be modified remain in contact with the plasma-moderated solution. The role of plasma-moderated liquids, allows the reach of the reactive species through solution onto the geometrically hindered sites. The UV radiation produced in plasma formation helps in generating additional excited, ionized, and dissociated molecules and species in the reaction solution. An interesting feature of the technique is its flexibility to use a wide variety of additives as or in solution system. This allows us to create a selective or monotype functionalization of material surfaces. Such system was studied for the selective hydroxyl functionalization of polypropylene surface. The oxidation of polymer surfaces and the introduction of O-containing functional groups by underwater plasma was found to exceed concentrations typically achieved in oxygen low-pressure gas discharge plasmas up-to two-folds (maximal 56 O/100 C). The fraction of OH groups among all O-containing moieties amounts from 25 to 40% in comparison to that in the gas plasma of about 10% OH groups. Addition of hydrogen peroxide into this same system increases the fraction of C—O bonds up to 75% (27-OH/100 O). A study was focused to optimize the role of hydrogen peroxide on the efficiency of oxidation and selectivity with chemical derivatization with respect to the formation of mono-sort hydroxyl functionalities, calculated using a chemical derivatization technique. KW - Capillary discharge KW - Functionalization of polymer KW - Modification surfaces KW - Underwater plasma KW - Surface modification KW - Polymer functionalization PY - 2009 DO - https://doi.org/10.1002/ppap.200930601 SN - 1612-8850 SN - 1612-8869 VL - 6 IS - Suppl. 1 SP - 5218 EP - 5222 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-22772 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -