1,332 research outputs found
Shape of a liquid front upon dewetting
We examine the profile of a liquid front of a film that is dewetting a solid
substrate. Since volume is conserved, the material that once covered the
substrate is accumulated in a rim close to the three phase contact line.
Theoretically, such a profile of a Newtonian liquid resembles an exponentially
decaying harmonic oscillation that relaxes into the prepared film thickness.
For the first time, we were able to observe this behavior experimentally. A
non-Newtonian liquid - a polymer melt - however, behaves differently. Here,
viscoelastic properties come into play. We will demonstrate that by analyzing
the shape of the rim profile. On a nm scale, we gain access to the rheology of
a non-Newtonian liquid.Comment: 4 pages, 4 figure
Slip vs viscoelasticity in dewetting thin films
Ultrathin polymer films on non-wettable substrates display dynamic features
which have been attributed to either viscoelastic or slip effects. Here we show
that in the weak and strong slip regime effects of viscoelastic relaxation are
either absent or not distinguishable from slip effects. Strong-slip modifies
the fastest unstable mode in a rupturing thin film, which questions the
standard approach to reconstruct the effective interface potential from
dewetting experiments.Comment: 4 pages, submitted to Eur. Phys. J.
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