Speaker
Astrid de Wijn
(Trondheim University)
Description
Superlubricity, or alternatively termed structural
(super)lubrictiy, is a concept where ultra-low friction is
expected at the interface between sliding surfaces if these
surfaces are incommensurate and thus unable to interlock. In
this work, we now report on sudden, reversible, friction
changes that have been observed during AFM based
nanomanipulation experiments of gold nanoparticles sliding
on highly oriented pyrolythic graphite. These effects are
can be explained by rotations of the gold nanoparticles
within the concept of structural superlubricity, where the
occurrence of ultra-low friction candepend extremely
sensitively on the relative orientation between the slider
and the substrate. From our theoretical simulations it will
become apparent how even miniscule magnitudes of rotation
are compatible to the observed effects and how size and
shape of the particles can influence the dependence between
friction and relative orientation.
