TY - JOUR A1 - Fahmy, A. A1 - Mix, Renate A1 - Schönhals, Andreas A1 - Friedrich, Jörg Florian T1 - Surface and bulk structure of thin spin coated and plasma-polymerized polystyrene films N2 - Polystyrene (PS) spin coated thin films were modified by O2 and Ar plasma as well as by UV irradiation treatments. The modified PS samples were compared with plasma polymerized and commercial polystyrene. The effects of plasma (O2 and Ar) and UV irradiation treatments on the surface and the bulk properties of the polymer layers were discussed. The surface properties were evaluated by X-ray Photoelectron Spectroscopy and Contact angle measurements and the bulk properties were investigated by FTIR and dielectric relaxation spectroscopy. As a result only one second treatment time was sufficient to modify the surface. However, this study was also dedicated to understand the effect of plasma and plasma irradiation on the deposited layers of plasma polymers. The dielectric measurements showed that the plasma deposited films were not thermally stable and underwent an undesired post-plasma chemical oxidation. KW - Surface and bulk characterization KW - Plasma polymerization KW - Polystyrene KW - Surface modification KW - Thermal stability KW - Plasma polymers PY - 2012 DO - https://doi.org/10.1007/s11090-012-9372-1 SN - 0272-4324 VL - 32 IS - 4 SP - 767 EP - 780 PB - Plenum Publ. Corp. CY - New York, NY, USA AN - OPUS4-26264 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fahmy, A. A1 - Friedrich, Jörg Florian T1 - Degradation behavior of thin polystyrene films on exposure to Ar plasma and its emitted radiation N2 - Spin-coated films of amorphous polystyrene (PS) were exposed to argon plasma for a few seconds to several minutes. The PS film was either in direct contact with the plasma or was shielded from the direct plasma contact by filters with different cutoff wavelengths in the vacuum UV region or by a Faraday cage (FC) made from metal mesh to prevent the impinging of charged species. Only energy-rich neutrals and plasma radiation may be operative in presence of the FC. lithium fluoride (LiF) filter protects the sample from direct contact with the plasma. Wavelengths of plasma radiation shorter than c. 105 nm (≈ 11.8 eV) were cut off. Glass filters made of fused SiO2 have a cutoff at λ ≈175?nm completely the vacuum UV radiation of plasma (ca. 175 nm ≈ 7.0 eV). These energies are sufficient to produce C–C, C–H bond scissions in case of direct Ar plasma exposure and Ar plasma exposure with use of the LiF filter. Only quartz glass shielding did not produce significant effects on the polymer surface in comparison to the reference PS, either in surface energy or O/C ratio or in IR spectra. Oxygen plasma has worked most aggressive and had etched the PS film, thus establishing a steady state between introduction of new oxygen functionalities and polymer etching. Ar plasma exposure produces also oxidation and etching of the polymer films as the oxygen plasma. Using of a FC during Ar plasma exposure or the LiF filter a slightly weaker oxidation was observed. KW - Polystyrene KW - Plasma treatment KW - Plasma emitted radiation KW - Degradation KW - Thin films PY - 2013 DO - https://doi.org/10.1080/01694243.2012.705528 SN - 0169-4243 SN - 1568-5616 VL - 27 IS - 3 SP - 324 EP - 338 PB - VNU Science Press CY - Utrecht AN - OPUS4-26315 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mohamed, Zeinab A1 - Krüger, Simone A1 - Hidde, Gundula A1 - Schimanski, A. A1 - Jäger, Christian A1 - Friedrich, Jörg Florian T1 - Deposition of thick polymer or inorganic layers with flame-retardant properties by combination of plasma and spray processes N2 - Mixtures of hexamethyldisiloxane (HMDSO) and oxygen have been used for deposition of SiO2-like layers by plasma polymerization under low-pressure conditions onto polyethylene and polystyrene used as basecoat. Water glass was cast onto these 0.5 µm plasma thick siloxane-like layers with a thickness of 5 to 40 µm. The adhesion of these bilayer systems and their flame resistance were tested. The effect of different plasma parameters such as monomer/gas ratio, pressure and power input into the discharge on the deposition rate and the composition of the formed layers was studied. Characterization and chemical composition of the formed films were performed using infrared, X-ray photoelectron and solid state nuclear magnetic resonance spectroscopy. Peel strengths of composites were measured and the locus of peel front propagation was detected. Thermal properties of composites were analyzed by thermo-gravimetric analysis. Finally, the fire-retardant properties of thick coated polymers were determined by exposure to flames and the behavior of coatings on the polymers during flaming was observed visually. KW - Plasma polymerization KW - Hexamethyldisiloxane plasma polymer KW - Polystyrene KW - Polyethylene KW - Flame retardancy PY - 2013 DO - https://doi.org/10.1016/j.surfcoat.2013.04.039 SN - 0257-8972 VL - 228 SP - 266 EP - 274 PB - Elsevier B.V. CY - Lausanne AN - OPUS4-28735 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -