ULTRA-LOW
FRICTION, WITHOUT LUBRICANTS, has been observed in an
experiment at the University of Basel in Switzerland,
with interesting implications for possible nanotech
applications.
The dragging of a
force microscope tip across the surface atoms of a
sample (size regime of one-billionth meter) is not
unlike the motion of underground tectonic blocks (size
scale of tens of thousands of meters): in both cases
the sideways motion of one object past another gets
stuck for a while until sufficient lateral force builds
up when motion is resumed, sometimes with a jerk and
a dissipation
of energy.
This "stick-slip"
syndrome---the main scenario for friction at the atomic
level---can be smoothed somewhat by lubricants, but
the new experiment at Basel shows that if the load
(the object on top) is made light enough it can slide
along a surface without any friction (and with no
lubricants present), at least not at a sensitivity
level of 10^-11 newtons.
According
to Enrico Gnecco +41-61-267-3725,
enrico.gnecco@unibas.ch
the glidingof a force microscope tip across a sample
was observed to undergo a transition from stick-slip
to continuous sliding, and that this be very useful
in the realm of nanoelectromechanical (NEM) devices,
where nano-sleds and nanocontainers might be moved
around with negligible dissipation.
|
