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 - 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 - Hinze, A. A1 - Klages, C.-P. A1 - Zänker, A. A1 - Thomas, M. A1 - Wirth, Thomas A1 - Unger, Wolfgang T1 - ToF-SIMS imaging of DBD-plasma-printed microspots on BOPP substrates N2 - Imaging ToF-SIMS has been applied to characterize the surface chemistry variations across small areas produced by a DBD-type plasma printing technique on a BOPP substrate using pure nitrogen and a nitrogen-hydrogen gas mixture. CH4N+ and CNO- secondary ions are detected with high yields remote from the discharge region. They are discussed to be due to surface modifications of the substrate by metastable gas-phase species. On the other hand, surface species exist that are preferentially formed by reactions of the substrate with short-lived species which are only present close to the plasma discharge region. A C3H8O+ secondary fragment ion is assumed to be a key fragment of such a surface species. KW - ToF-SIMS KW - Plasma KW - Polymer KW - Dielectric barrier discharges (DBD) KW - Plasma printing KW - Polymer modification KW - Surface modification KW - Time-of-flight secondary-ion mass spectroscopy (ToF-SIMS) imaging PY - 2008 DO - https://doi.org/10.1002/ppap.200700138 SN - 1612-8850 SN - 1612-8869 VL - 5 IS - 5 SP - 460 EP - 470 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-19342 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gross, Thomas A1 - Kühn, Gerhard A1 - Unger, Wolfgang T1 - Photoelectron spectroscopy on organic surfaces: X-ray degradation of oxygen-plasma-treated and chemically reduced poly(propylene) surfaces in comparison to conventional polymers N2 - The X-ray-induced sample damage during mono XPS analysis of an oxygen-plasma-oxidized and subsequently wet-chemically reduced poly(propylene) film was investigated as a showcase for plasma-modified or plasma-deposited samples. By doing this, the degradation index approach as introduced by Beamson and Briggs in the Scienta ESCA300 high-resolution XPS database of organic polymers has been adopted. As to be expected, the sample degrades by loosing oxygen as revealed by observation of decreasing O/C and COR/Csum ratios. However, the X-ray degradation indices are definitely higher than those of conventional reference polymers. Moreover, the COR/Csum degradation index is significantly higher in comparison with one obtained for the O/C ratio. In that context, there is no difference between the plasma sample and a conventional poly(vinyl alcohol) polymer. It is concluded that for reliable quantitative surface chemical analysis, the quality of spectra in terms of acquisition times must be optimized aimed to a minimization of X-ray degradation. Finally, it is proposed to describe the photon flux of an X-ray gun in an XPS experiment, which defines the degradation rate at the end, by using the sample current simply measured with a carefully grounded sputter-cleaned reference silver sample. KW - Photoelectron spectroscopy KW - ESCA/XPS KW - Surfaces KW - Surface modification KW - Poly(propylene) (PP) KW - Plasma treatment KW - X-ray KW - Degradation PY - 2009 DO - https://doi.org/10.1002/sia.3024 SN - 0142-2421 SN - 1096-9918 VL - 41 IS - 5 SP - 445 EP - 448 PB - Wiley CY - Chichester AN - OPUS4-19252 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hoffmann, Katrin A1 - Mix, Renate A1 - Friedrich, Jörg Florian A1 - Buschmann, H.-J. A1 - Resch-Genger, Ute T1 - Anchoring of Fluorophores to plasma-chemically modified polymer surfaces and the effect of Cucurbit[6]uril on dye emission N2 - Polypropylene supports were functionalized by plasma-deposition of polymeric allylamine layers. The surface amino groups generated were wet-chemically reacted with xanthene dyes resulting in fluorescent polymer films. The effect of polymer-attachment of the dyes on their emission features was studied fluorometrically and different methods were tested to improve the fluorescence properties of the films. Modification with cucurbit[6]uril (CB6) yields a moderately enhanced fluorescence as well as an improved photostability. The observed effect is most likely due to CB6-induced rigidization of the linker molecules which seems to reduce fluorescence quenching dye–dye and fluorophore–surface interactions. KW - Fluorescence KW - Cucurbituril KW - Surface modification KW - Plasma functionalization KW - Polymer surface KW - Xanthene dyes PY - 2009 DO - https://doi.org/10.1007/s10895-008-0407-1 SN - 1053-0509 SN - 1573-4994 VL - 19 SP - 229 EP - 237 PB - Plenum Publ. Corp. CY - New York, NY AN - OPUS4-19154 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Safinia, L. A1 - Dantan, Nathalie A1 - Höhse, Marek A1 - Mantalaris, A. A1 - Bismarck, A. T1 - Towards a methodology for the effective surface modification of porous polymer scaffolds N2 - A novel low-pressure radio-frequency plasma treatment protocol was developed to achieve the effective through-thickness surface modification of large porous poly (d,l-lactide) (PDLLA) polymer scaffolds using air or water: ammonia plasma treatments. Polymer films were modified as controls. Scanning electron micrographs and maximum bubble point measurements demonstrated that the PDLLA foams have the high porosity, void fraction and interconnected pores required for use as tissue engineering scaffolds. The polymer surface of the virgin polymer does contain acidic functional groups but is hydrophobic. Following exposure to air or water: ammonia plasma, an increased number of polar functional groups and improved wetting behaviour, i.e. hydrophilicity, of wet surfaces was detected. The number of polar surface functional groups increased (hence the decrease in water contact angles) with increasing exposure time to plasma. The change in surface composition and wettablility of wet polymer constructs was characterised by zeta potential and contact angle measurements. The hydrophobic recovery of the treated PDLLA polymer surfaces was also studied. Storage of the treated polymer constructs in ambient air caused an appreciable hydrophobic recovery, whereas in water only partial hydrophobic recovery occurred. However, in both cases the initial surface characteristics decay as function of time. KW - Scaffold KW - Polyactic acid KW - Plasma KW - Surface modification KW - Contact angle KW - Wettability hydrophilicity PY - 2005 DO - https://doi.org/10.1016/j.biomaterials.2005.05.078 SN - 0142-9612 VL - 26 IS - 36 SP - 7537 EP - 7547 PB - Elsevier CY - Oxford AN - OPUS4-11487 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Geng, Sh. A1 - Friedrich, Jörg Florian A1 - Gähde, J. A1 - Guo, L. T1 - Surface-Enhanced Infrared Absorption (SEIRA) and Its Use in analysis of Plasma-Modified Surface KW - Plasma KW - IR KW - Surface-enhanced infrared absorption (SEIRA) KW - Surface modification PY - 1999 SN - 0021-8995 SN - 1097-4628 VL - 71 SP - 1231 EP - 1237 PB - Wiley InterScience CY - Hoboken, NJ AN - OPUS4-6985 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müeller, W.-D. A1 - Gross, U. A1 - Fritz, Th. A1 - Voigt, Ch. A1 - Fischer, P. A1 - Berger, Georg A1 - Rogaschewski, S. A1 - Lange, K.-P. T1 - Evaluation of the interface between bone and titanium surfaces being blasted by aluminium oxide or bioceramic particles N2 - The surface structure, in particular the surface roughness, and the surface chemistry of titanium implants influence their anchoring in bone. The aim of this study was to analyse metal-bone contact (MBC) after modification of the implant surface, using different materials for blasting. The surface modification of titanium was produced by blasting it with particles made of Al2O3 or bioceramics. The biological effects were then investigated experimentally using 27 rabbits, analysed after 7, 28 and 84 days after the implantation of titanium cylinders treated accordingly. The MBC showed a tendency for more bone after bioceramics were used as a blasting material, compared to Al2O3. KW - Dental implants KW - Surface modification KW - Animal experiment KW - Bioceramics PY - 2003 DO - https://doi.org/10.1034/j.1600-0501.2003.00791.x SN - 0905-7161 SN - 1600-0501 VL - 14 IS - 3 SP - 349 EP - 356 PB - Blackwell Munksgaard CY - Oxford AN - OPUS4-3506 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -