@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{SoutoRodriguezMendezPenacoradaetal.1997, author = {Souto, Jorge and Rodriguez-Mendez, Maria-Luisa and Penacorada, Florencio and Reiche, J{\"u}rgen}, title = {Small angle x-ray reflectivity study of Langmuir-Blodgett films of a peripherally substituted zinc phthalocyanine}, year = {1997}, abstract = {Langmuir-Blodgett films of zinc 11,18,25-tri(tert-butyl)-4-sulfo-phthalocyanine (ZNPctSO3Na) have been deposited onto hydrophilic and hydrophobic silicon wafers. Y-type films were formed on both types of substrate, and the transfer ratio was very close to unity. The organization of the films on the molecular level was probed by X-ray specular reflectivity.}, language = {en} } @article{PenacoradaReicheZetzscheetal.1997, author = {Penacorada, Florencio and Reiche, J{\"u}rgen and Zetzsche, Thomas and Dietel, Reinhard and Brehmer, Ludwig and Saja, Jose-Antonio de}, title = {Stabilisation of fatty acid mono- and multilayers by simultaneous polyelectrolyte complexation and salt formation with cadmium ions}, year = {1997}, abstract = {The complexation of highly ordered fatty acid monolayers with polyelectrolytes is expected to yield well- ordered Langmuir films suitable for the formation of Langmuir-Blodgett multilayers with improved long-term stability. Studies of the surface pressure-area isotherms and of the surface potential kinetics yield detailed information regarding the influence of these polymeric counterions on the monolayer properties. The injection of bivalent metal salts into the subphase after the complexation was used to improve the order and stability of the mono- and multilayers. The corresponding Langmuir-Blodgett films were investigated by means of X-ray reflectivity measurements and scanning force microscopy. The polyion complex multilayers show a strongly increased mechanical stability compared with films of fatty acid salts formed with bivalent metal ions. These structures are expected to be suitable as ultrathin separation layer for gas separation or ultrafiltration membranes.}, 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{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} } @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{BolmEnglischPenacoradaetal.1997, author = {Bolm, A. and Englisch, Uwe and Penacorada, Florencio and Gerstenberger, M. and Pietsch, Ullrich}, title = {Temperature and time dependent investigations of cd- and uranyl-stearate multilayers by means of neutron reflectivity measurements}, year = {1997}, language = {en} } @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{EnglischPenacoradaBrehmeretal.1999, author = {Englisch, Uwe and Penacorada, Florencio and Brehmer, Ludwig and Pietsch, Ullrich}, title = {X-ray and neutron reflection analysis of the structure and the molecular exchange process in simple and complex fatty acid salt Langmuir-Blodgett multilayers}, year = {1999}, language = {en} }