@article{NeumannBuchsteinerMahleretal.2000, author = {Neumann, Werner and Buchsteiner, Alexandra and Mahler, Willy and Geue, Thomas and Pietsch, Ullrich}, title = {Dielectric loss spectroscopy at fatty acid salt multilayers}, year = {2000}, abstract = {Dielectric loss spectroscopy (DLS) was performed at compact samples and lamellary organized Langmuir-Blodgett (LB) films from various fatty acid salts. Previous thermoanalytical measurements at compact samples revealed the appearance of two different phase transition temperatures; the lower one is related to the acid the second one to the acid salt molecules. In spite of ill defined electrical contacts with the film the characteristic DLS frequencies obtained from about 100nm thick multilayer films are similar to those recorded from bulk samples. No significant variations of frequencies were found changing the counter ions. Besides conductivity influence at low frequncies we found two relaxations related to the mobility of the dipolar carboxylat-metal group at about 100 and 10000Hz. One of these frequencies is related to the rotation around the chain axis. The strength of this relaxation increases significantly with increasing the sample temperature above 105°C. This temperature is connected with a structural phase transition observed by X-ray reflectometry. In case of Pb-stearate the results of the dielectric measurements help to interprete this structural change as a transition from an orthorhombic into a free-rotator phase. The uncorrelated rotation of molecules around their molecular axes initiates a much increased relaxation strength at the carboxylat-metal sites.}, language = {en} } @article{StahnGeueGrenzeretal.2000, author = {Stahn, Jochen and Geue, Thomas and Grenzer, J{\"o}rg and Pietsch, Ullrich}, title = {Interaction of short-chain alkanes with surface and interfaces of multilayer films built from amphiphilic molecules: an in-situ X-ray and neutron scattering probe}, year = {2000}, language = {en} } @article{KarcenkoEnglischGrenzeretal.2000, author = {Karcenko, Anatolij V. and Englisch, Uwe and Grenzer, J{\"o}rg and Geue, Thomas and Pietsch, Ullrich and Siebrecht, R.}, title = {Investigation of partially deuterated multilayers by means of X-ray and polarized neutron reflectometry}, issn = {1044-8632}, year = {2000}, language = {en} } @article{MukherjeeBhattacharyaSanyaletal.2000, author = {Mukherjee, M. and Bhattacharya, M. K. and Sanyal, M. K. and Geue, Thomas and Grenzer, J{\"o}rg and Pietsch, Ullrich}, title = {Temperature dependent thickness and surface tension of polymer films}, isbn = {81-7371295-6}, year = {2000}, language = {en} } @article{GeueSchultzGrenzeretal.2000, author = {Geue, Thomas and Schultz, Michael and Grenzer, J{\"o}rg and Natansohn, Almeria and Rochon, Paul}, title = {X-ray investigations of the molecular mobility with polymer surface gratings}, year = {2000}, language = {en} }