@article{AngelovaPenacoradaStilleretal.1994, author = {Angelova, Angelina and Penacorada, Florencio and Stiller, Burkhard and Zetzsche, Thomas and Ionov, Radoslav and Kamusewitz, Helmut and Brehmer, Ludwig}, title = {Wettability, surface morphology and stability of long chain ester multilayers obtained by different Langmuir- Blodgett deposition type}, year = {1994}, language = {en} } @article{PenacoradaDietelReicheetal.1995, author = {Penacorada, Florencio and Dietel, Reinhard and Reiche, J{\"u}rgen and Zetzsche, Thomas and Knobloch, Harald and Katholy, Stefan and Brehmer, Ludwig}, title = {Studium des Einflusses von Uranyl-Gegenionen auf die Struktur von Langmuir- und Langmuir-Blodgett Filmen der Arachins{\"a}ure}, year = {1995}, language = {de} } @article{ReichePenacoradaZetzscheetal.1995, author = {Reiche, J{\"u}rgen and Penacorada, Florencio and Zetzsche, Thomas and Katholy, Stefan and Brehmer, Ludwig}, title = {Polyelektrolyt-Fetts{\"a}ure-Multiphasen-LB-Schichten}, year = {1995}, language = {de} } @article{PenacoradaYusupovMilaskietal.1995, author = {Penacorada, Florencio and Yusupov, R. G. and Milaski, B. and Fr{\"u}bing, Peter and Brehmer, Ludwig}, title = {Elektrische Eigenschaften von polyionischen LB-Filmen}, year = {1995}, language = {de} } @article{ReichePenacoradaGeueetal.1995, author = {Reiche, J{\"u}rgen and Penacorada, Florencio and Geue, Thomas and Pietsch, Ullrich and Brehmer, Ludwig}, title = {In-plane structure of uranylarachidate multilayers}, year = {1995}, language = {en} } @article{PenacoradaReicheKatholyetal.1995, author = {Penacorada, Florencio and Reiche, J{\"u}rgen and Katholy, Stefan and Brehmer, Ludwig and Rodriguez-Mendez, Maria-Luisa}, title = {Monolayers and multilayers of uranyl arachidate : 1. study of the interaction of dissolved uranyl ions with arachidic acid Langmuir monolayers}, year = {1995}, abstract = {Langmuir monolayers of arachidic acid have been prepared on a subphase containing uranyl ions (O-U-O){\´y}+. 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 Cd{\´y}+ 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 Cd{\´y}+. 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.}, language = {en} } @article{PenacoradaAngelovaKamusewitzetal.1995, author = {Penacorada, Florencio and Angelova, Angelina and Kamusewitz, Helmut and Reiche, J{\"u}rgen and Brehmer, Ludwig}, title = {Scanning Force Microscopy and Wetting study of the Surface Modification of a Polypropylene Mambrane by Means of Langmuir-Blodgett Film Deposition}, year = {1995}, abstract = {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.}, language = {en} } @article{DietelPenacoradaBrehmer1995, author = {Dietel, Reinhard and Penacorada, Florencio and Brehmer, Ludwig}, title = {Structural variations in Langmuir-Blodgett layers of arachidic acid studied by FTIR-reflection absorption spectroscopy}, year = {1995}, language = {en} } @article{PenacoradaReicheDieteletal.1996, author = {Penacorada, Florencio and Reiche, J{\"u}rgen and Dietel, Reinhard and Zetzsche, Thomas and Stiller, Burkhard and Knobloch, Harald and Brehmer, Ludwig}, title = {Monolayers and multilayers of uranyl arachidate : 2. Influence of the subphase pH on the structure and stability of Langmuir-Blodgett films}, year = {1996}, abstract = {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.}, language = {en} } @article{PapraPenacoradaReicheetal.1997, author = {Papra, Alex and Penacorada, Florencio and Reiche, J{\"u}rgen and Katholy, Stefan and Brehmer, Ludwig and Hicke, Hans-Georg}, title = {Structure and Stability of Langmuir Monolayers and Langmuir-Blodgett Films of Bisaroyl Azide Bolaamphiphiles}, year = {1997}, abstract = {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}, language = {en} }