Direct observations of dewetting process on interface of soft gels

Qin Xu (Soft and Living Materials, D-MATL)

Wetting of liquid droplets on soft gels deforms gel interface significantly: a wetting ridge grows under the balance between liquid surface tension and solid surface stress near contact line. Using interference microscopy and fast camera imaging, we directly observe the recovery of gel surface from this wetting-induced deformation after removing liquid droplet. We show experimentally that surface relaxation of soft gels cannot be simply modelled by their viscoelastic rheology. Instead, the internal flow of free chains through elastic network is very rather important. Our results extend the current understanding of elastocapillarity with the effect of bulk porosity, and bring new insight into the study of wetting dynamics on soft materials.

Overview Materials Colloquium 2019