Molecular dynamics simulations of friction between an ordered organic monolayer and a rigid slider with an atomic scale protrusion

Takuya Ohzono and Masamichi Fujihira

Department of Biomolecular Engineering, Tokyo Institute of Technology,
4259 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan

The atomic scale friction between an ordered organic monolayer and a rigid probing slider with an atomic scale protrusion was investigated using a molecular dynamics method. The slider was used to model the tip apex used in the atomic force microscopy. In order to control the normal load, three orthogonal springs and a feedback regulation unit were introduced. The protrusion composed of a small number of atoms brought about local and collective deformation of the monolayer and generated friction force. Various frictional properties were investigated in terms of the size of the protrusion, the length of molecules in the monolayer, and the conditions, such as temperature, applied normal load, and some parameters for the external observation system. The lattice-resolved friction signals were obtained when the size of the protrusion is comparable to that of the cross sectional area of the molecule.

References
1) Takuya Ohzono and Masamichi Fujihira, Jap. J. Appl. Phys., 39, 6029-6034 (2000).
2) Takuya Ohzono and Masamichi Fujihira, Phys. Rev. B, 62, 17055-17071 (2000).
3) Takuya Ohzono and Masamichi Fujihira, Tribol. Lett., 63-67 (2000).