Berlin 2008 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 25: Polyelectrolytes
CPP 25.6: Vortrag
Mittwoch, 27. Februar 2008, 15:45–16:00, C 230
Wrinkling for measuring charge density effects in polyelectrolyte multilayers and as a novel approach towards templating — •Ingo Doench1, Conghua Lu1, Patrick Ott2, André Laschewsky3, and Andreas Fery1,4 — 1Max Planck Institute of Colloids and Interfaces, Potsdam, Germany — 2Universität Potsdam, Germany — 3Fraunhofer Institute for Applied Polymer Research, Potsdam, Germany — 4University of Bayreuth, Germany
Polyelectrolyte Multilayers find various applications as coatings or semi-permeable membranes. Their mechanical properties are relevant for stability as well as in general for their deformation properties (pressure sensing). Still, classical indentation tests for determining mechanical properties of solid-supported films face serious problems due to substrate effects when the film thickness is below a micron. Therefore, we use an alternate approach in which we investigate wrinkling of these films and derive elastic constants from the measurement of the wrinkle period. We are able to change the charge density of the polycation for film preparation and find that this .allows tuning the mechanical properties of the multilayers. Furthermore, humidity has strong effects on the multilayers and we find that the degree of softening / swelling of the multilayers by increasing humidity can be determined by the charge density as well. Apart from the possibility to determine elastic constants of thin films, wrinkling provides a simple pathway to lithography-free topographical patterning on the micron- and sub-micron-scale. We present first results for templating of colloidal particle-deposition and discuss perspectives.