%0 Generic
%A Kurz, Volker Luiz Siegmar
%D 2010
%F heidok:11613
%K thin films , polymer , spectroscopy , phase transition
%R 10.11588/heidok.00011613
%T Orientation, conformation and phase transitions of thin polymer films and self-assembled monolayers studied by SFG spectroscopy
%U https://archiv.ub.uni-heidelberg.de/volltextserver/11613/
%X The aim of this dissertation was the characterization of thin polymeric  lms on metal substrates. Of special interest were  lms of poly-N-isopropylacrylamide (pNIPAM). Their lower critical solution temperature (LCST) at 32°C makes this polymer attractive for many applications. The changes in the molecular structure and the dynamic of these changes at the LCST are related to macroscopic properties. Using inherently interface speci c sum-frequency generation spectroscopy, gave insights into the molecular arrangement even through bulk media. The molecular groups responsible for the phase transition were identi ed and the infuence of the molecular weight was analyzed. Order parameters were also deduced. In order to obtain quantitative information from the SFG spectra a spectral simulation program was implemented allowing for quanti cation of molecular orientation in the polymer  films investigated. The composition of an n-layer system of the sample, angle of incidence, and molecular symmetry groups were used as parameters. Furthermore, the existing SFG spectrometer was adapted to investigate the solid/liquid interface using a freshly developed in situ cell as well as a novel pulse shaping technique allowing for the clear separation of the spectral phase of vibrational resonances. A reference beam line for absolute intensity measurements was also added. In addition, samples of self assembled monolayers of oligo(ethylene glycol) OEG, often used as model systems for the understanding of anti fouling materials, were investigated. The e ect of di erent aqueous environments, temperatures, chain lengths and terminal groups on the conformations of the molecules in the  lm were characterized.