la6b01209_si_001.avi (4 MB)
Tuning the Receding Contact Angle on Hydrogels by Addition of Particles
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posted on 2016-05-17, 00:00 authored by François Boulogne, François Ingremeau, Laurent Limat, Howard
A. StoneControl of the swelling,
chemical functionalization, and adhesivity
of hydrogels are finding new applications in a wide range of material
systems. We investigate experimentally the effect of adsorbed particles
on hydrogels on the depinning of contact lines. In our experiments,
a water drop containing polystyrene microspheres is deposited on a
swelling hydrogel, which leads to the drop absorption and particle
deposition. Two regimes are observed: a decreasing drop height with
a pinned contact line followed by a receding contact line. We show
that increasing the particles concentration increases the duration
of the first regime and significantly decreases the total absorption
time. The adsorbed particles increase the pinning force at the contact
line. Finally, we develop a method to measure the receding contact
angle with the consideration of the hydrogel swelling.