Berlin 2012 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 7: Poster: Biopolymers and Biomaterials (jointly with BP)

CPP 7.5: Poster

Montag, 26. März 2012, 17:30–19:30, Poster A

(Visco-)Elasticity and thickness determination of polyelectrolyte multilayers by atomic force microscopy — •Johannes Hellwig, Cagri Üzüm, and Regine von Klitzing — Stranski-Laboratorium, Department of Chemistry, TU Berlin, Strasse des 17. Juni 124, D-10623 Berlin

Thin films of polyelectrolyte multilayers can be easily prepared by using the Layer-by-Layer technique. These films show different growth behaviour, e.g. linearly or non-linearly, and also different mechanical properties. Mechanical properties can be influenced by the hard substrate below the film. Therefore the film thickness has to be taken into consideration. The growth behaviour and film thickness of PEMs can be determined by different methods using an Atomic Force Microscope (AFM). A common method called *scratch method* and a newly presented method called *full-indentation* was used to determine the thickness of soft films with a double layer number of 12 * 96. It was shown that both methods agree well within the experimental errors. In addition the elastic modulus of the films was determined by using an Colloidal Probe AFM where a colloidal probe attached to the end of a cantilever was indented into the PEM film. The mechanical properties of the PEMs was calculated from the deflection of the cantilever with a Herzian based elasticity model. Latest research focus on the non-elastic behaviour of PEMs.