Dewetting liquid film on a soft substrate

Soft solids play an important role in stretchable electronics, cellular membranes and water collection. Upon introduction of a liquid contact line, soft solids can deform substantially causing changes to geometry and dynamics. On the nanoscale, surface tension at the solid/liquid contact line can deform a soft solid creating a capillary ridge. We study these capillary ridges for a system which consists of a thin polymer film in the melt state atop an elastomeric poly(dimethylsiloxane) film, placed on a rigid Silicon substrate. The liquid polymer layer dewets on the soft PDMS base. We vary the thickness of the underlying elastomer film, which changes the effective stiffness, therefore changing the size of the capillary ridge. The size of the capillary ridge affects the energy dissipation of the system as the dewetting rim retracts. We use optical and atomic force microscopy to study the statics and dynamics of this system.