Dresden 2017 – wissenschaftliches Programm
CPP 49.1: Poster
Mittwoch, 22. März 2017, 18:30–21:00, P2-OG1
3D Depth Profiles of the Tip-Sample Interaction on Compliant Polymers — •Martin Dehnert and Robert Magerle — Fakultät für Naturwissenschaften, Technische Universität Chemnitz, Germany
Attractive forces between the tip of an atomic force microscope and a polymer melt or a swollen polymer act over several tens of nanometers. The tip indentation into these compliant materials is of similar size. Both effects cause a large uncertainty in height measurements. Here we compare 3D depth profiles of the tip-sample interaction measured with force-distance (FD) and amplitude-phase-distance (APD) measurements. In particular, we compare the height profiles reconstructed from different characteristic points on FD and APD curves that might characterize the unperturbed surface position: (a) the onset of attractive forces, (b) the contact point where attractive and repulsive forces balance each other, and (c) the position of the maximal attractive force in FD measurements. All three geometrical quantities do not require assumptions about material properties or a specific contact model. As examples, we study polystyrene melts with low molecular weight and polystyrene droplets swollen in solvent vapor. A solid Si wafer serves as substrate and height reference. Our approach allows for accurate height and 3D shape measurements of compliant polymeric nanostructures.