Dünne Filme - Steuerung kristalliner Morphologien über Strukturbildung auf mikroheterogenisierten Oberflächen

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Non-equilibrium growth processes on surfaces produce typical morphological features which are mainly influenced by the diffusion behaviour of components to the growth front of the structural unit. The morphological patterns from diffusion limited aggregation processes are therefore very similar even for very different systems such as the growth patterns from solidification processes or the growth of bacteria on substrates.For crystallisation in thin films of polyethylene in contact with hererogeneous surfaces we found that crystallisation and dewetting appear as competitive processes. Chemically heterogeneous gold surfaces with locally different free surface energies are prepared by micro-contactprinting with 12-undecanthiocarboxylicacid. The films formed on the heterogenized surfaces exhibit different morphological features within the different surface areas. Film morphologies show features characteristic for dewetting as well as for diffusion controlled crystal growth processes. The examination of films is preferently done by AFM and LVSEM.Future experiments focus on a more detailled investigation between the morphological features (including crystallographic fine structure of ultrathin polymer films) which are related to the film formation on heterogenized surfaces with domains of different size ... and shape.Parallel to the crystallisation PE a rigid-rod polymer (Poly-(di-n-hexylsilan)) in ultrathin films on heteronenized surfaces should be investigated. From kinetical investigations of other groups an influence of surface properties of the kinetics has been found and quantified in terms of Avrami kinetics. Our experiments will focus on the question how morphological structures in the Poly-(di-n-hexylsilan) can be influenced by control of the underlying surface.