Tuning Hierarchical Topographical and Chemical Surface Patterns
Konstantinos Roumpos, University of Freiburg
Prof. Günter Reiter, University of Freiburg
The objectives of this research project are to generate and study the evolution of hierarchical topographical patterns in thin polymer films governed by film instabilities and the release of elastic energy stored in these films and to explore the physical and rheological properties of supported and freely standing thin polymer films. More specifically, the interactions of thin polymer layers with fiber network-decorated surfaces (contact mechanics, adhesion forces, crack formation) have been studied, with the outlook of generating plant-inspired topographies. Key parameters, such as the temperature, the thicknesses of the polymer films, their thermal history and preparation conditions, have been varied in order to tune the emerging patterns. Moreover, the rheological behavior of thin films on patterned substrates has been studied. We were successful in transferring the pattern of the substrate on the polymer film by means of dewetting and in quantifying the forces acting on the film during this process. The resulting patterns have been compared with patterns found on plant surfaces, like the surface cell layer on plant leaves.