Volume 95, Number 3, August 2011
|Number of page(s)||6|
|Section||Condensed Matter: Structural, Mechanical and Thermal Properties|
|Published online||12 July 2011|
Molecular-dynamics simulation of lateral friction in contact-mode atomic force microscopy of alkane films: The role of molecular flexibility
Facultad de Física, Pontificia Universidad Católica de Chile - Casilla 306, Santiago, Chile
2 Department of Chemistry, Technical University of Denmark - IK 207 DTU, DK-2800 Lyngby, Denmark, EU
3 Department of Physics and Astronomy and University of Missouri Research Reactor, University of Missouri Columbia, MO 65211, USA
4 Centro para el Desarrollo de la Nanociencia y la Nanotecnología, CEDENNA - Avda. Ecuador 3493, Santiago, Chile
Accepted: 15 June 2011
Molecular-dynamics simulations are used to investigate lateral friction in contact-mode atomic force microscopy of tetracosane (n-C24H50) films. We find larger friction coefficients on the surface of monolayer and bilayer films in which the long axis of the molecules is parallel to the interface than on a surface of molecules with the long axis perpendicular to the surface, in agreement with experimental results. A major dissipation mechanism is the molecular flexibility as manifested in the torsional motion about the molecules’ C-C bonds. The generation of gauche defects as a result of this motion does not appear to be in itself a major channel of energy dissipation. As previously reported in the literature, the layer density and thereby the strength of the attractive film-tip interaction is also an important factor in energy dissipation.
PACS: 68.37.Ps – Atomic force microscopy (AFM) / 68.35.Af – Atomic scale friction / 31.15.xv – Molecular dynamics and other numerical methods
© EPLA, 2011
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.