Dresden 2011 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 6: Charged Soft Matter
CPP 6.5: Vortrag
Montag, 14. März 2011, 15:00–15:15, ZEU 160
Novel Concept for Reporting Pressure - fields based on Mechanoresponsive Polyelectrolyte Brushes — •Johann Erath1, Johanna Bünsow2, Wilhelm T. S. Huck2,3, and Andreas Fery1 — 1Physical Chemistry II, University Bayreuth, 95440, Bayreuth, Germany — 2Melville Laboratory for Polymer Synthesis, Department of Chemistry, University of Cambridge, Cambridge CB21EW, UK — 3Radboud University Nijmegen, Institute for Molecules and Materials, 6525 AJ Nijmegen, The Netherlands
Determination of pressure fields is of interest for both, fundamental science (e.g. mapping force fields in bio-adhesion) and application (e.g. robotics). The aim of this contribution is to introduce a novel concept for self-reporting force sensors based on mechanoresponsive polyelectrolyte brushes, which translate deformation directly into changes in fluorescence intensity. Experiments were performed with a combination of an atomic force microscope with a confocal laser scanning microscope. Using the soft colloidal probe technique, we compressed the polyelectrolyte brushes in the direction normal to the surface. Compression leads to a drop of the fluorescence intensity in the brush. Likewise, upon retracting the bead from the surface, a tension was exerted onto the polymer strands situated at the edge of the bead which induced an increase of the fluorescence signal. The response of the polyelectrolyte brushes to compression was completely reversible. On the basis of the JKR theory, we developed a qualitative understanding of the force distribution underneath the PDMS bead, which shows that the sensor does response to compression and tension in one frame.