TY - JOUR A1 - Reiche, Jürgen A1 - Dietel, Reinhard A1 - Lemmetyinen, Helge A1 - Janietz, Dietmar A1 - Lemmetyinen, Helge A1 - Brehmer, Ludwig T1 - Edge-on Langmuir-Blodgett multilayers derived from disc-shaped multiyne mesogens N2 - Langmuir-Blodgett(LB) multilayers were prepared from disc-shaped multiyne mesogens based on amphiphilic alkyl pentakis(aryl-ethynyl)benzene ethers. The two compounds used are characterized by five hydrophobic flexible chains and one hydrophilic substituent at the terminal position of the alkoxy chain. The LB films were analysed by X-ray scattering and spectroscopic measurements. An edge-on arrangement of the two discotic pentaalkynes within Y-type bilayers with a different packing density proved to be possible for the LB films of both compounds. Y1 - 1992 ER - TY - JOUR A1 - Reiche, Jürgen A1 - Zetzsche, Thomas A1 - Helms, Andreas A1 - Freydank, Anke-Christine A1 - Knochenhauer, Gerald A1 - Schulz, Burkhard A1 - Brehmer, Ludwig T1 - Organized molecular films of oxadiazole compounds formed by vacuum deposition Y1 - 1997 ER - TY - JOUR A1 - Penacorada, Florencio A1 - Angelova, Angelina A1 - Kamusewitz, Helmut A1 - Reiche, Jürgen A1 - Brehmer, Ludwig T1 - Scanning Force Microscopy and Wetting study of the Surface Modification of a Polypropylene Mambrane by Means of Langmuir-Blodgett Film Deposition N2 - Polypropylene membranes with deposited ultrathin "siin" layers are attractive for separation and cleaning of gaseous mixtures. In the present study, the surface morphology and wetting hysteresis of composite membranes consisting of a microporous polypropylene support and Langmuir-Blodgett ("skin") films, are investigated. The effect of the interlayer molecular interactions and the substrate features on the integrity and homogeneity of the "skin" layers is examined. Langmuir-Blodgett films of arachidic acid and cadmium and calcium arachidate are characterized both on smooth silicon and on porous polypropylene supports. Contact angle measurements and scanning force microscopy (SFM) are applied for investigations of the membrane surface modification upon transfer of a different number of monolayers. It was found that the contact angle hysteresis of the bare membrane decreases after the LB-deposition of close-packed monolayers. Smoothing of the membrane surface is also evidenced by the SFM images, on different length scales, confirming a good coverage of the membrane pores. Y1 - 1995 ER - TY - JOUR A1 - Reiche, Jürgen A1 - Janietz, Dietmar A1 - Barberka, Thomas Andreas A1 - Hofmann, Dieter A1 - Brehmer, Ludwig T1 - Comprehensive structure investigation of Langmuir-Blodgett films of disc-shaped molecules N2 - The structure of mono- and multilayers of amphiphilic disc-shaped pentaynes wa inbestigated by Brewsterangle microscopy, X-ray specular reflection and grazing incidence diffraction (GID). X-ray specular reflection experiments confirm the "edge on" arrangement of the molecular discs. The molecular modelling of the Langmuir-Blodgett (LB)- multilayers predicts a columnar in-plane packing of the molecules. A GID experiment with monochromatic synchrotron radiation was used to verify the predicted multilayer structure on molecular level, while the Brewsterangle microscopy gave a deeper insight in the monolayer in-plane structure on micron scale. Y1 - 1995 ER - TY - JOUR A1 - Penacorada, Florencio A1 - Reiche, Jürgen A1 - Katholy, Stefan A1 - Brehmer, Ludwig A1 - Rodriguez-Mendez, Maria-Luisa T1 - Monolayers and multilayers of uranyl arachidate : 1. study of the interaction of dissolved uranyl ions with arachidic acid Langmuir monolayers N2 - Langmuir monolayers of arachidic acid have been prepared on a subphase containing uranyl ions (O-U-O)ý+. The interaction between the uranyl ions and the monolayer of arachidic acid has been studied by means of surface pressure and surface potential isotherms and Brewster angle microscopy at different pH values (ranging from 1.5 to 8). A similar systematic study has been carried out in the presence of Cdý+ ions for comparison purposes. The surface pressure and surface potential isotherms demonstrate that the acid to salt conversion of arachidic acid in the presence of uranyl ions occurs at lower bulk pH values (pH=3.5) as compared with other bivalent metal counterions such as Cdý+. Changes in the surface morphology of the monolayer induced by the interaction with uranyl- and cadmium ions are analyzed and the correlation between the surface potential change and the morphology of the films is discussed. Y1 - 1995 ER - TY - JOUR A1 - Reiche, Jürgen A1 - Freydank, A. A1 - Dietzel, Birgit A1 - Katholy, Stefan A1 - Knochenhauer, Gerald A1 - Zetzsche, Thomas A1 - Schulz, Burkhard A1 - Brehmer, Ludwig T1 - Komplexe Strukturanalytik von Oxadiazol-Mono- und Multischichten Y1 - 1995 ER - TY - JOUR A1 - Reiche, Jürgen A1 - Penacorada, Florencio A1 - Geue, Thomas A1 - Pietsch, Ullrich A1 - Brehmer, Ludwig T1 - In-plane structure of uranylarachidate multilayers Y1 - 1995 ER - TY - JOUR A1 - Brehmer, Ludwig A1 - Dietzel, Birgit A1 - Freydank, Anke-Christine A1 - Katholy, Stefan A1 - Knochenhauer, Gerald A1 - Reiche, Jürgen A1 - Schulz, Burkhard A1 - Zetzsche, Thomas T1 - Langmuir- und Langmuir-Blodgett-Filme amphiphiler Oxadiazole Y1 - 1995 ER - TY - JOUR A1 - Geue, Thomas A1 - Katholy, Stefan A1 - Reiche, Jürgen A1 - Brehmer, Ludwig A1 - Caliebe, W. T1 - Grazing incidence x-ray diffraction (GIXD) measurements of uranyl arachidate (UO2A2) LB films Y1 - 1998 ER - TY - JOUR A1 - Reiche, Jürgen A1 - Knochenhauer, Gerald A1 - Barberka, Thomas Andreas A1 - Geue, Thomas A1 - Pietsch, Ullrich A1 - Brehmer, Ludwig A1 - Hodge, P. A1 - Tredgold, Richard H. T1 - In-plane structure of perfluorotetra decanoic acid Langmuir-Blodgett films and films formed by vacuum deposition Y1 - 1995 ER -