TY - JOUR A1 - Angelova, Angelina A1 - Penacorada, Florencio A1 - Stiller, Burkhard A1 - Zetzsche, Thomas A1 - Ionov, Radoslav A1 - Kamusewitz, Helmut A1 - Brehmer, Ludwig T1 - Wettability, surface morphology and stability of long chain ester multilayers obtained by different Langmuir- Blodgett deposition type Y1 - 1994 ER - TY - JOUR A1 - Penacorada, Florencio A1 - Dietel, Reinhard A1 - Reiche, Jürgen A1 - Zetzsche, Thomas A1 - Knobloch, Harald A1 - Katholy, Stefan A1 - Brehmer, Ludwig T1 - Studium des Einflusses von Uranyl-Gegenionen auf die Struktur von Langmuir- und Langmuir-Blodgett Filmen der Arachinsäure Y1 - 1995 ER - TY - JOUR A1 - Reiche, Jürgen A1 - Penacorada, Florencio A1 - Zetzsche, Thomas A1 - Katholy, Stefan A1 - Brehmer, Ludwig T1 - Polyelektrolyt-Fettsäure-Multiphasen-LB-Schichten Y1 - 1995 ER - TY - JOUR A1 - Penacorada, Florencio A1 - Yusupov, R. G. A1 - Milaski, B. A1 - Frübing, Peter A1 - Brehmer, Ludwig T1 - Elektrische Eigenschaften von polyionischen LB-Filmen 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 - 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 - 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 - Dietel, Reinhard A1 - Penacorada, Florencio A1 - Brehmer, Ludwig T1 - Structural variations in Langmuir-Blodgett layers of arachidic acid studied by FTIR-reflection absorption spectroscopy Y1 - 1995 ER - TY - JOUR A1 - Penacorada, Florencio A1 - Reiche, Jürgen A1 - Dietel, Reinhard A1 - Zetzsche, Thomas A1 - Stiller, Burkhard A1 - Knobloch, Harald A1 - Brehmer, Ludwig T1 - Monolayers and multilayers of uranyl arachidate : 2. Influence of the subphase pH on the structure and stability of Langmuir-Blodgett films N2 - In this second paper we describe the comprehensive structure investigations on multilayers of uranyl arachidate formed by Langmuir-Blodgett deposition from subphases of different pH on solid substrates by means of a combination of infrared spectroscopy, X-ray specular reflection, ellipsometry, and scanning force microscopy, The structure of these multilayers and their stability are obviously influenced by the subphase pH. The pH range of the acid to salt conversion determined for the Langmuir films is confirmed by the infrared spectroscopic data of the multilayers. While arachidic acid films, deposited from an uranyl acetate subphase of low pH, are found to have strongly distorted rough surface, the films of uranyl structure, The influence of the counterions on the alkyl chain conformation, chain packing, reorganization probability, and stability of the multilayer is discussed. Y1 - 1996 ER - TY - JOUR A1 - Papra, Alex A1 - Penacorada, Florencio A1 - Reiche, Jürgen A1 - Katholy, Stefan A1 - Brehmer, Ludwig A1 - Hicke, Hans-Georg T1 - Structure and Stability of Langmuir Monolayers and Langmuir-Blodgett Films of Bisaroyl Azide Bolaamphiphiles N2 - Langmuir-Blodgett films of bolaamphiphiles with reactive head groups can be used for the surface modification of composite membranes for gas separation processes. The scope of our investigations was to get a detailed insight in the monolayer behaviour and LB film structure of previously synthesized bisaroyl azide bolaamphiphiles. The layers have been analyses by means of surface potential measurements and Brewster angle microscopy. Furthermore parameters for a successful LB Film deposition were found. As expected for a molecule with two hydrophilic ends the transfer ratio on upstroke was close to one and on downstroke no transfer occurred. The multilayer structure was analysed by scanning force microscopy and X-ray reflectivity measurements. The SFM images revealed a periodic in plane structure on molecular level. Based on a combination of the X-ray data with results of other methods two possible models of the multilayer structure are presented Y1 - 1997 ER -