Theoretische und experimentelle Untersuchungen von Benetzungseigenschaften von dünnen ein- und zweikomponentigen Polymerfilmen

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Stabilisation of thin polymer films is of great practical importance for many applications in physics, chemistry, medicine, biology and material science. Utilising the spin-coating technique thin polymer films can be prepared on a large variety of different solid substrates including also non-wetting surfaces, where films are not stable. Different processes can contribute to film destabilisation during annealing above the glass transition temperature. Those effects are studied in the already running project on model systems. Real systems are, however, significantly different for instance due to the influence of substrate roughness and chemical inhomogeneity. A systematic study of those effects is still largely missing. Besides the influence of substrate parameters also the chemical nature of used polymer molecules is of importance. For instance block copolymers can be used for film stabilisation, but are also interesting because of the formation of ordered structures on themselves. The dewetting of block copolymers on solid substrates has hardly been studied up to now.In this project it is proposed to investigate the influence of substrate properties (roughness and chemical heterogeneity), which will be modified in a well defined way, as well as porticular plymer properties on the stabilisation of the film. The time scale of dewetting is taken as a measure of film stability. With scattering techniques we obtain information on a large sample area, which is characteristic for the dewetting process. By the use of local imaging techniques a picture of different aspects of stability and dewetting is obtained on different length scales.