TY  - JOUR
A1  - Englisch, Uwe
A1  - Katholy, Stefan
A1  - Penacorada, Florencio
A1  - Reiche, Jürgen
A1  - Pietsch, Ullrich
T1  - Investigation of molecular diffusion across organic multilayers using neutron specular reflectivity
Y1  - 1999
ER  - 
TY  - JOUR
A1  - Knochenhauer, Gerald
A1  - Penacorada, Florencio
A1  - Reiche, Jürgen
A1  - Brehmer, Ludwig
A1  - Tredgold, Richard H.
A1  - Barberka, Thomas Andreas
T1  - Multilayers of perfluorinated fatty acids
N2  - We have formed Y layers of perfluorododecanoic acid CF3(CF2)10COOH by thermal evaporation in vacuo and of perfluorotetradecanoic acid CF3(CF2)12COOH by thermal evaporation and by the Langmuir-Blodgett (LB) technique. We have obtained the bilayer spacing of both these materials by X-ray diffraction and have also studied the in-plane structure of these materials by means of grazing incidence diffraction (GID). Computer modelling was used to interpret the results obtained. For the perfluorododecanoic acid, we find two stable untwisted phases at 25°C and a combination of these two predicts both the Bragg peaks arising from the layer structure and the GID results. Our experimental results show that the perfluorotetradecanoic acid exists in the generally accepted helical structure. Computer modelling leads to the conclusion that closely packed perfluorinated chains with 12 or less carbon atoms should exist in an untwisted state while molecules having more than 12 carbon atoms show the onset of the helical conformation.
Y1  - 1999
ER  - 
TY  - JOUR
A1  - Englisch, Uwe
A1  - Penacorada, Florencio
A1  - Brehmer, Ludwig
A1  - Pietsch, Ullrich
T1  - X-ray and neutron reflection analysis of the structure and the molecular exchange process in simple and complex fatty acid salt Langmuir-Blodgett multilayers
Y1  - 1999
ER  -