Dresden 2003 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
CPP: Chemische Physik und Polymerphysik
CPP 22: POSTER C
CPP 22.28: Poster
Donnerstag, 27. März 2003, 12:00–14:00, ZEU/250
Mapping Mechanical Properties of Soft Surfaces by Means of AFM Noise Analysis — •Farida Benmouna1, Diethelm Johannsmann2, and Tatiana Dimitrova1 — 1MPI for Polymer Research, D-55128 Mainz — 2Institute of Physical Chemistry, TU Clausthal, D?38678, Clausthal-Zellerfeld
It has been demonstrated that AFM noise analysis allows performing local mechanical spectroscopy. In low-viscosity environments, the power spectral density of the cantilever’s displacement is given by resonance curves. From them one obtains an effective spring constant, a friction coefficient, and an effective mass. We built an AFM-based state-of-the-art instrument, and performed 3D mapping of the mechanical properties of soft surfaces. The instrument has feedback-controlled 3-channel nano-positioning and real time analysis of the noise power spectra. Its imaging capabilities were employed to correlate near-surface structure of polymer films with mechanical behavior of the filaments, formed when the AFM tip is withdrawn from the surface. The films were formed from polyacrylic latices and their surface has granular structure. We demonstrate that the micro-mechanical properties as well as the length of the elongated filaments depend on the spatial position of the AFM- tip. The most filaments (which appear the longest) originate from the center of the individual particles. Almost no fibrillation is observed when the tip hits the interstices between the particles.