TY - JOUR A1 - Friedrich, Jörg Florian A1 - Kühn, Gerhard A1 - Mix, Renate A1 - Fritz, Andreas A1 - Schönhals, Andreas T1 - Polymer surface modification with monofunctional groups of variable types and densities N2 - The retention of chemical structure and functional groups during pulsed plasma polymerization was used for producing adhesion-promoting plasma polymer layers with high concentrations of exclusively one kind of functional groups, such as OH, NH2, or COOH. The maximum content of functional groups was 31 OH using allyl alcohol, 18 NH2 using allylamine, or 24 COOH per 100 C atoms using acrylic acid. To vary the density of functional groups, chemical co-polymerization with ethylene as 'chain-extending' co-monomer, or butadiene as 'chemical crosslinker' was initiated in the pulsed plasma. The composition of these co-polymers was investigated by XPS and IR spectroscopy. The concentrations of functional groups were measured by derivatizing with fluorine-containing reagents and using XPS. A set of plasma parameters was found to be a good compromise between a high number of functional groups and complete insolubility in water, ethanol or THF,which is needed for further chemical processing. Here, these monotype-functionalized surfaces were used in metal-polymer systems as adhesion-promoting interlayers to examine the influence of type and density of functional groups on adhesion. As expected, COOH- and OH-group-terminated interlayers showed maximum peel strengths to evaporated aluminium layers. The adhesion increased linearly with the number of OH groups to a maximum at about 27 OH per 100 C atoms. Higher concentrations of OH groups did not increase the peel strength further. KW - Co-polymers KW - Adhesion-promoting interlayers KW - Metal-polymer systems PY - 2003 DO - https://doi.org/10.1163/156856103322396695 SN - 0169-4243 SN - 1568-5616 VL - 17 IS - 12 SP - 1591 EP - 1617 PB - VNU Science Press CY - Utrecht AN - OPUS4-2704 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Friedrich, Jörg Florian A1 - Schönhals, Andreas A1 - Fritz, Andreas A1 - Mix, Renate A1 - Kühn, Gerhard ED - d'Agostino, R. T1 - Pulsed plasma initiated homo and copolymerisation - characterization of thin plasma polymer layers by dielectric relaxation spectroscopy T2 - 16th International Symposium on Plasma Chemistry (ISPC-16) CY - Taormina, Italy DA - 2003-06-22 PY - 2003 IS - CD-ROM PB - Dep. of Chemistry, Univ. CY - Bari AN - OPUS4-2711 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fritz, Andreas A1 - Schönhals, Andreas A1 - Mix, Renate A1 - Kühn, Gerhard A1 - Friedrich, Jörg Florian T1 - Dielectric spectroscopy of plasma copolymers of the system allyl alcohol/alkene N2 - Polymers synthesized with plasma techniques are very interesting materials for electronic, optic, and bio compatible applications. Thin films of plasma polymers shows a good adhesion to metals, glass, or other polymers. But the supramolecular structure, the durability, and the chemical and mechanical behavior of these polymers is poorly understood. Therefore dielectric investigations are carried out to study the dynamic behavior of the plasma polymers. As polymer system allyl alcohol/alkene is chosen to get polymers with a defined concentration of hydroxyl groups. The dielectric investigations shows several relaxation processes and a dependency of the dielectric parameters from the ratio of allyl alcohol in the polymer is observed. This results indicated that the alkene monomers were assembled continuous into the polymer matrix. T2 - Frühjahrstagung des Arbeitskreises Festkörperphysik bei der DPG CY - Regensburg, Deutschland DA - 2002-03-11 PY - 2002 UR - http://old.dpg-tagungen.de/archive/2002/cpp_4.html SN - 0420-0195 SN - 0372-5448 SN - 0343-9216 IS - CPP 4.7 SP - 424 CY - Bad Honnef AN - OPUS4-2057 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fritz, Andreas A1 - Schönhals, Andreas A1 - Mix, Renate A1 - Kühn, Gerhard A1 - Friedrich, Jörg Florian T1 - Dielectric spectroscopy of plasma copolymers or the system allyl alcohol/alkene T2 - Frühjahrstagung des Arbeitskreises Festkörperphysik bei der DPG CY - Regensburg, Germany DA - 2002-03-11 PY - 2002 SN - 0420-0195 SN - 0372-5448 SN - 0343-9216 IS - CPP 4.7 SP - 424 CY - Bad Honnef AN - OPUS4-2058 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fritz, Andreas A1 - Schönhals, Andreas A1 - Sapich, B. A1 - Stumpe, J. T1 - Dynamic and photochemical behavior of amorphous comb-like copolymers with photochromic azobenzene side groups N2 - A series of amorphous photochromic homo- and copolymethacrylates with an azobenzene moiety in the side group is investigated systematically by optical and dielectric spectroscopy. The aliphatic ester component of the comonomer unit and the concentration of the azobenzene groups within the copolymer are varied. The kinetics and the temperature dependence of the E/Z (trans/cis) photoisomerization and of the thermal Z/E (cis/trans) isomerization is studied for spin-coated films of the polymers. To understand the polarity of the polymeric materials as well as the matrix dependence of the reactions and of the photoinduced reorientation processes in the steady state molecular dynamics is investigated by dielectric spectroscopy. A variety of relaxation processes is observed: a γ-relaxation at low temperatures followed by a β-, an α-, and a δ-process. Additionally at room temperature a new -relaxation is detected for polymers containing azobenzene moieties. The temperature dependence of the reaction rate of the thermal Z/E isomerization process measured by optical spectroscopy seems to correlate with the values of the β'-process. A correspondence between dielectric and photochemical behavior is discussed. PY - 1999 SN - 1022-1352 SN - 1521-3935 VL - 200 IS - 10 SP - 2213 EP - 2220 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-13687 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schönhals, Andreas A1 - Fritz, Andreas A1 - Pfeiffer, K. T1 - Characterization of the crosslinking kinetics of a thin polymeric layer by real-time dielectric relaxation spectroscopy N2 - The crosslinking kinetic of a thin polymeric layer based on a prepolymer of a phthalic aciddiallylester was studied by real-time dielectric spectroscopy in the frequency range from 10-1 to 105 Hz. With increasing reaction time the real part of the dielectric function ε ´ decreases. The time dependence of ε ´ can be described by a stretched exponential function with a stretching exponent of 0.5. This means that the influence of the chemical reaction on ε ´ cannot be described by a first order kinetic. From the temperature dependence of the characteristic time constant an activation energy of 71 kJ/mol could be estimated for the reaction. From the dielectric loss data the change of the relaxation rate of the dynamic glass transition fpα with the reaction time is obtained. After a temperature dependent induction period fpα decreases very strongly. No plateau value which corresponds to a glass transition in the crosslinked system is obtained for long reaction times. PY - 2001 SN - 1022-1352 SN - 1521-3935 VL - 202 IS - 16 SP - 3228 EP - 3233 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-13698 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sapich, B. A1 - Fischer, T. A1 - Haferkorn, J. A1 - Geue, T. A1 - Fritz, Andreas A1 - Schönhals, Andreas A1 - Date, R. A1 - Fawcett, A. A1 - Stumpe, J. T1 - Anisotropic films of poly(olefin sulfone)s with cinnamoyl side groups prepared by self-organisation and photoreactions T2 - Liquid Crystals and its practical application PY - 2006 VL - 4 IS - 18 SP - 9 EP - 21 AN - OPUS4-14594 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schönhals, Andreas A1 - Hardy, L. A1 - Fritz, Andreas A1 - Stevenson, I. A1 - Boiteux, G. A1 - Seytre, G. T1 - Dielectric relaxation behaviour of poly(ethylene naphthalene 2,6 dicarboxylate) (PEN) N2 - Dielectric spectroscopy has been used to study poly(ethylene naphthalene 2,6 dicarboxylate) (PEN) samples of different morphologies obtained by thermally treating bi-axially stretched PEN films. Neat and thermally treated samples of PEN films have been characterised by differential scanning calorimetry in order to measure the glass transition and melting temperatures as well as the degrees of crystallinity. Dielectric analysis has allowed the observation of the evolution of molecular relaxation phenomena with morphology changes and has revealed three relaxation processes: ?-, ?*- and ?-relaxation (increasing temperature). The ?-relaxation is associated with local motions of ester and the ?*-relaxation with partially cooperative motions of naphthalene groups. The latter has been shown to be related to the morphology of the materials under study. The ?-relaxation associated to the glass transition of PEN corresponds to cooperative motions induced by conformational rearrangements of the main chain and depends also on the morphology of the PEN films. Dielectric relaxation behaviours were compared using the activation energies calculated from Arrhenius equation formalism for the two sub-glass processes. Vogel–Fulcher–Tammann fits were performed on the ?-relaxation. Our important contribution for the bi-axially stretched PEN films study is related to the assignment of the ?*-relaxation that can be attributed to naphthalene aggregates. PY - 2002 DO - https://doi.org/10.1016/S0022-3093(02)01104-3 SN - 0022-3093 VL - 305 SP - 174 EP - 182 PB - North-Holland Publ. Co. CY - Amsterdam AN - OPUS4-1570 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schönhals, Andreas A1 - Goering, Harald A1 - Böhning, Martin A1 - Fritz, Andreas A1 - Rübner, J. T1 - Structure Analysis of Polymeric Nanomaterials by Relaxation Spectroscopy T2 - Polydays 2002 CY - Berlin, Germany DA - 2002-09-30 PY - 2002 SP - 1(?) AN - OPUS4-2044 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Böhning, Martin A1 - Goering, Harald A1 - Fritz, Andreas A1 - Brzezinka, Klaus-Werner A1 - Turky, Gamal A1 - Schönhals, Andreas A1 - Schartel, Bernhard T1 - Dielectric Study of Molecular Mobility in Poly(propylene-graft-maleic anhydride)/Clay Nanocomposites N2 - Polymer/clay nanocomposite materials based on poly(propylene-graft-maleic anhydride) (PPgMAH) and two different organophilic modified clays were investigated by dielectric relaxation spectroscopy (DRS). In contrast to ungrafted polypropylene (PP), PPgMAH shows a dielectrically active relaxation process which can be assigned to localized fluctuations of the polar maleic anhydride groups. Its relaxation rate exhibits an unusual temperature dependence, which could be attributed to a redistribution of water molecules in the polymeric matrix. This is confirmed by a combination of Raman spectroscopy and thermogravimetric experiments (TGA) with real-time dielectric measurements under controlled atmospheres. In the nanocomposites this relaxation process is shifted to higher frequencies up to 3 orders of magnitude compared to the unfilled polymer. This indicates a significantly enhanced molecular mobility in the interfacial regions. In the nanocomposite materials a separate high-temperature process due to Maxwell-Wagner-Sillars (MWS) polarization was observed. The time constant of this MWS process can be correlated with characteristic length scales in nanocomposites and therefore provides additional information on dispersion and delamination/exfoliation of clay platelets in these materials. These properties also influence the diffusivity of the water molecules as revealed by real-time dielectric investigations. KW - Polymer clay nanocomposites KW - Molecular mobility KW - Dielectric relaxation spectroscopy PY - 2005 DO - https://doi.org/10.1021/ma048315c SN - 0024-9297 SN - 1520-5835 VL - 38 IS - 7 SP - 2764 EP - 2774 PB - American Chemical Society CY - Washington, DC AN - OPUS4-7281 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -