Speaker
Astrid de Wijn
(Trondheim University)
Description
A unique path to control and ultimately manipulate forces
between material surfaces is through an applied electric
field. Several experimental and theoretical studies of
electro chemical interfaces demonstrated that the
orientation of polar molecules adsorbed at electrode
surfaces is potential dependent. We propose a theoretical
model for friction under electrochemical conditions focusing
on the interaction of a force microscope tip with adsorbed
polar molecules of which the orientation depends on the
applied electric field. The dependence of friction force on
the electric field is shown to be determined by the
interplay of two channels of energy dissipation: (i) the
rotation of dipoles and (ii) slips of the tip over potential
barriers. The molecule geometry and oscillating fields are
investigated as well.
[1] Nanoscopic friction under electrochemical control, A. S.
de Wijn, A. Fasolino, A. Filippov, M. Urbakh, Phys. Rev.
Lett. 112, 055502 (2014).
[2] Effects of molecule anchoring and dispersion on
nanoscopic friction under electrochemical control, A. S. de
Wijn, A. Fasolino, A. E. Filippov, and M. Urbakh, J. Phys.:
Condens. Matter 28, 105001 (2016).
