TY - JOUR A1 - Mukherjee, M. A1 - Bhattacharya, M. K. A1 - Sanyal, M. K. A1 - Geue, Thomas A1 - Grenzer, Jörg A1 - Pietsch, Ullrich T1 - Temperature dependent thickness and surface tension of polymer films Y1 - 2000 SN - 81-7371295-6 ER - TY - JOUR A1 - Geue, Thomas A1 - Schultz, Michael A1 - Grenzer, Jörg A1 - Natansohn, Almeria A1 - Rochon, Paul T1 - X-ray investigations of the molecular mobility with polymer surface gratings Y1 - 2000 ER - TY - JOUR A1 - Geue, Thomas A1 - Pietsch, Ullrich A1 - Haferkorn, J. A1 - Stumpe, Joachim A1 - Date, R. W. A1 - Fawcett, A. H. T1 - Competition of alignment and aggregation? : Phenomena in constrained films of LC poly(olefin ulfone)s and maleic anhydride co- and terpolymers Y1 - 1999 ER - TY - JOUR A1 - Reiche, Jürgen A1 - Freydank, Anke-Christine A1 - Helms, Andreas A1 - Geue, Thomas A1 - Schulz, Burkhard A1 - Brehmer, Ludwig A1 - Stiller, Burkhard A1 - Knochenhauer, Gerald T1 - Vacuum deposition films of oxadiazole compounds : formation and structure investigation N2 - The search for alternative routes of organic thin film formation is stimulated by the outstanding properties of these films in such fields as nonlinear optics, photonic data processing and molecular electronics. The formation of highly ordered multilayer structures by thermal vacuum deposition (VD) of organic compounds is an essential step toward the application of supramolecular organic architectures in technical systems. The VD of an amphiphilic substituted 2,5- diphenylene-1,3,4-oxadiazole 1 onto silicon substrates at defined temperature was used for the formation of ultrathin films. The structural data obtained for the VD-films of oxadiazole 1 by means of X-ray reflectivity, X-ray grazing incidence diffraction and atomic force microscopy (AFM) investigations indicate the formation of well ordered oxadiazole multilayers. The structure of the VD-multilayers is compared with that of Langmuir-Blodgett (LB) films and thermally treated LB-multilayers prepared from the same compound. Y1 - 1999 ER - TY - JOUR A1 - Geue, Thomas A1 - Schultz, M. A1 - Englisch, Uwe A1 - Stömmer, Ralph A1 - Pietsch, Ullrich A1 - Meine, Kerstin A1 - Vollhard, D. T1 - Investigation of pH-dependent domain structure of fatty acid salt Langmuir-Blodgett films by means of X-ray diffuse scattering and Atomic Force Microscopy Y1 - 1999 ER - TY - JOUR A1 - Henneberg, Oliver A1 - Geue, Thomas A1 - Saphiannikova, Marina A1 - Pietsch, Ullrich A1 - Rochon, Paul A1 - Natansohn, Almeria T1 - Formation and dynamics of polymer surface relief gratings Y1 - 2001 SN - 0378-5963 ER - TY - JOUR A1 - Henneberg, Oliver A1 - Chi, Li Feng A1 - Geue, Thomas A1 - Saphiannikova, Marina A1 - Pietsch, Ullrich A1 - Rochon, Paul A1 - Natansohn, Almeria T1 - Atomic force microscopy inspection of the early state of formation of polymer surface relief grating Y1 - 2001 ER - TY - JOUR A1 - Geue, Thomas A1 - Saphiannikova, Marina A1 - Henneberg, Oliver A1 - Pietsch, Ullrich A1 - Rochon, Paul A1 - Natansohn, Almeria T1 - Formation mechanism and dynamics in polymer surface gratings Y1 - 2002 ER - TY - JOUR A1 - Stiller, Burkhard A1 - Geue, Thomas A1 - Morawetz, Knut A1 - Saphiannikova, Marina T1 - Optical patterning in azobenzene polymer films N2 - Thin azobenzene polymer films show a very unusual property, namely optically induced material transport. The underlying physics for this phenomenon has not yet been thoroughly explained. Nevertheless, this effect enables one to inscribe different patterns onto film surfaces, including one- and two-dimensional periodic structures. Typical sizes of such structures are of the order of micrometers, i.e. related to the interference pattern made by the laser used for optical excitation. In this study we have measured the mechanical properties of one- and two-dimensional gratings, with a high lateral resolution, using force-distance curves and pulse force mode of the atomic force microscope. We also report on the generation of considerably finer structures, with a typical size of 100 nm, which were inscribed onto the polymer surface by the tip of a scanning near-field optical microscope used as an optical pen. Such inscription not only opens new application possibilities but also gives deeper insight into the fundamentals physics underlying optically induced material transport Y1 - 2005 SN - 0022-2720 ER - TY - JOUR A1 - Saphiannikova, Marina A1 - Geue, Thomas A1 - Henneberg, Oliver A1 - Morawetz, Knut A1 - Pietsch, Ullrich T1 - Linear viscoelastic analysis of formation and relaxation of azobenzene polymer gratings N2 - Surface relief gratings on azobenzene containing polymer films were prepared under irradiation by actinic light. Finite element modeling of the inscription process was carried out using linear viscoelastic analysis. It was assumed that under illumination the polymer film undergoes considerable plastification, which reduces its original Young's modulus by at least three orders of magnitude. Force densities of about 10(11) N/m(3) were necessary to reproduce the growth of the surface relief grating. It was shown that at large deformations the force of surface tension becomes comparable to the inscription force and therefore plays an essential role in the retardation of the inscription process. In addition to surface profiling the gradual development of an accompanying density grating was predicted for the regime of continuous exposure. Surface grating development under pulselike exposure cannot be explained in the frame of an incompressible fluid model. However, it was easily reproduced using the viscoelastic model with finite compressibility. (C) 2004 American Institute of Physics Y1 - 2004 U6 - https://doi.org/10.1063/1.1642606 ER - TY - JOUR A1 - Henneberg, Oliver A1 - Geue, Thomas A1 - Saphiannikova, Marina A1 - Pietsch, Ullrich A1 - Rochon, Paul T1 - X-ray and VIS light scattering from light-induced polymer gratings Y1 - 2003 UR - http://stacks.iop.org/0022-3727/36/A241 U6 - https://doi.org/10.1088/0022-3727/36/10A/350 ER - TY - JOUR A1 - Henneberg, Oliver A1 - Panzner, Tobias A1 - Pietsch, Ullrich A1 - Geue, Thomas A1 - Saphiannikova, Marina A1 - Rochon, Paul A1 - Finkelstein, Kenneth D. T1 - X-ray and VIS light scattering from light-induced polymer gratings N2 - Sinusoidally shaped surface relief gratings made of polymer films containing, azobenzene moieties can be created by holographic illumination with laser light of about lambda approximate to 500 nm. The remarkable material transport takes place at temperatures far (100 K) below the glass transition temperature of the material. As probed by visible light scattering the efficiency of grating formation crucially depends on the polarization state of the laser light and is maximal when circular polarization is used. In contrast to VIS light scattering X-ray diffraction is most sensitive for periodic surface undulations with amplitudes below 10 nm. Thus, combined in-situ X-ray and visible light scattering at CHESS were used to investigate the dynamics of surface relief grating formations upon laser illumination. The time development of grating peaks up to 9th order at laser power of P = 20 mW/cm(2) could be investigated, even the onset of grating formation as a function of light polarization. A linear growth of grating amplitude was observed for all polarizations. The growth velocity is maximal using circularly polarized light but very small for s-polarized light Y1 - 2004 UR - 1960 = doi:10.1524/zkri.219.4.218.30438 SN - 0044-2968 ER - TY - JOUR A1 - Henneberg, Oliver A1 - Geue, Thomas A1 - Saphiannikova, Marina A1 - Natansohn, Almeria A1 - Rochon, Paul A1 - Finkelstein, Kenneth D. T1 - Investigation of material flow on inscribing a polymer surface grating probing X-ray and VIS light scattering Y1 - 2002 SN - 0927-7757 ER - TY - JOUR A1 - Pietsch, Ullrich A1 - Geue, Thomas A1 - Henneberg, Oliver A1 - Saphiannikova, Marina T1 - X-ray investigations of formation efficiency of buried azobenzene polymer density gratings Y1 - 2003 UR - http://scitation.aip.org/journals/doc/JAPIAU-ft/vol_93/iss_6/3161_1.html U6 - https://doi.org/10.1063/1.1554753 ER - TY - JOUR A1 - Stiller, Burkhard A1 - Karageorgiev, Peter A1 - Geue, Thomas A1 - Morawetz, Knut A1 - Saphiannikova, Marina A1 - Mechau, Norman A1 - Neher, Dieter T1 - Optically induced mass transport studied by scanning near-field optical- and atomic force microscopy N2 - Some functionalised thin organic films show a very unusual property, namely the light induced material transport. This effect enables to generate three-dimensional structures on surfaces of azobenzene containing films only caused by special optical excitation. The physical mechanisms underlying this phenomenon have not yet been fully understood, and in addition, the dimensions of structures created in that way are macroscopic because of the optical techniques and the wavelength of the used light. In order to gain deeper insight into the physical fundamentals of this phenomenon and to open possibilities for applications it is necessary to create and study structures not only in a macroscopic but also in nanometer range. We first report about experiments to generate optically induced nano structures even down to 100 nm size. The optical stimulation was therefore made by a Scanning Near-field Optical Microscope (SNOM). Secondly, physical conditions inside optically generated surface relief gratings were studied by measuring mechanical properties with high lateral resolution via pulse force mode and force distance curves of an AFM Y1 - 2004 SN - 0204-3467 ER -