Berlin 2015 – scientific programme
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O: Fachverband Oberflächenphysik
O 101: Scanning Probe Techniques: AFM
O 101.3: Talk
Friday, March 20, 2015, 11:00–11:15, MA 144
High Resolution at High Viscosity - Dynamic Force Microscopy at Low Q-Factors — •Stefan Weber1,2, Jason Kilpatrick2, Timothy Brosnan2, Victor Bergmann1, Suzanne Jarvis2, and Brian Rodriguez2 — 1Physics of Interfaces, Max Planck Institute for Polymer Research, Mainz, Germany — 2Conway Institute of Biomedical and Biomolecular Research, University College Dublin, Dublin, Ireland
Atomic force microscopy (AFM) is often used in non-aqueous liquid environments for in situ investigations of processes including chemical reactions, lubrication and molecular ordering. These environments often exhibit a much higher damping, lowering the quality factor (Q) of the cantilever resonance. It is generally expected that AFM operation in such environments will not yield atomic scale resolution due to increased noise resulting in a reduced signal-to-noise ratio (SNR).
Recently, we have demonstrated that true atomic resolution can be obtained in a highly viscous environment. In particular, we imaged the atomic structure of highly ordered pyrolytic graphite (HOPG) and mica surfaces with SNR values comparable to ultra-high vacuum systems (Weber, S.A.L., et al., Nanotech., 2014. 25(17): p. 175701). We also investigated the influence of the Q-factor of a cantilever on the thermal noise of the relevant AFM signals, namely amplitude, phase and frequency shift. This new understanding of the noise contributions to the imaging process opens up a new route to high resolution AFM studies in a wide range of viscous fluids.