Influence of surface morphology on the adhesion of marine organisms

M.P. Arpa Sancet, X. Cao, F. Wode, A. Rosenhahn, M. Grunze

Applied Physical Chemistry, University of Heidelberg, Germany

Understanding the response of marine organisms to different surface properties is an important prerequisite for the development of improved antifouling coatings. Besides surface chemistry, the topography of surfaces is known to influence adhesion of fouling organism. As in nature many surfaces developed a topography in the micrometer- or nanometer range, the goal of the presented work is to prepare bioinspired surface morphologies and to systematically vary their size centered around the one found in nature. By evaluating the response of selected marine organisms, structure sizes with effect on the target fouling organisms are identified. The synthetic polyelectrolyte multilayers are constructed by the deposition of oppositely charged polyelectrolytes through layer-by-layer deposition. Hierarchical surface structures with different texture sizes and roughnesses were obtained by adjusting the preparation conditions. A modification of the obtained surfaces is achieved by the application of organosilanes by CVD or from solution. Ulva assays revealed that settlement and adhesion strength is significantly affected by texture size and surface chemistry. Interestingly, even for surfaces with resistant surface chemistries, the morphological influence can still be observed. At present we extend the experiments towards adhesion strength of marine bacteria. This is done by exerting a variable shear stress to adherent bacteria and quantification of the cell number by light microscopy. Ethylene glycol containing self assembled monolayers (SAMs) with different hydration are used as first benchmark system to prove the applicability of the new microfluidic setup.