Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published September 7, 2013 | Published
Journal Article Open

Molecular dynamic simulation of tip-polymer interaction in tapping-mode atomic force microscopy

Abstract

We present a molecular dynamic study of the interaction between an amorphous silica tip (SiO_2) and an amorphous poly-(methyl-methacrylate) substrate under conditions relevant for tapping-mode atomic force microscopy. To capture the actual dynamics of the tip, we use the dynamic contact simulation method [Kim et al., J. Appl. Phys. 112, 094325 (2012)]. We obtain force-displacement relationships both for neat polymer substrates and a sample with a sub-surface nanotube and extract the local stiffness and energy dissipation per cycle. The simulations capture non-trivial aspects of the interaction that originate from the viscoelastic nature of the polymer including an increase in repulsive interaction force during approach with tip velocity and an increase in adhesion during retraction with decreasing tip velocity. Scans of local stiffness and dissipation over the samples reveal intrinsic variability in the amorphous polymer but also the effect of local surface topography on the extracted properties as well as the ability of the method to detect a sub-surface nanotube. This insight and quantitative data should be valuable to interpret the results of atomic force microscopy studies.

Additional Information

© 2013 American Institute of Physics Publishing LLC. Received 8 April 2013; accepted 18 August 2013; published online 6 September 2013. This work was supported by the Dow Chemical Company and the US NNSA Center for the Prediction of Reliability, Integrity and Reliabilty of Microsystems (PRISM). Computational resources of nanoHUB.org and useful discussions with A. Raman are gratefully acknowledged.

Attached Files

Published - 1.4820256.pdf

Files

1.4820256.pdf
Files (3.5 MB)
Name Size Download all
md5:93268960c6b3a9c8d5b59cd6423f1eee
3.5 MB Preview Download

Additional details

Created:
August 19, 2023
Modified:
October 25, 2023