Abstract
We revisit the fundamental problem of liquid-liquid dewetting and perform a detailed comparison of theoretical predictions based on thin-film models with experimental measurements obtained by atomic force microscopy. Specifically, we consider the dewetting of a liquid polystyrene layer from a liquid polymethyl methacrylate layer, where the thicknesses and the viscosities of both layers are similar. Using experimentally determined system parameters like viscosity and surface tension, an excellent agreement of experimentally and theoretically obtained rim profile shapes are obtained including the liquid-liquid interface and even dewetting rates. Our new energetic approach additionally allows to assess the physical importance of different contributions to the energy-dissipation mechanism, for which we analyze the local flow fields and the local dissipation rates. Using this approach, we explain why dewetting rates for liquid-liquid systems follow no universal power law, despite the fact that experimental velocities are almost constant. This is in contrast to dewetting scenarios on solid substrates and in contrast to previous results for liquid-liquid substrates using heuristic approaches.
Highlights
The evolution of many physical systems is governed by thermodynamical or mechanical energetic principles[1,2,3,4]
As a model system we consider a layer of viscous liquid polystyrene (PS) Ω above a viscous liquid substrate consisting of polymethyl methacrylate (PMMA) Ωs
Conducting a full simulation of the sharp interface thin-film model for Newtonian liquids without any a priori assumptions on rim shape development or energy dissipation we obtained a full agreement with experimentally determined interface shapes and dewetting dynamics using the relevant experimental parameters like viscosities, aspect ratios, and surface energies
Summary
As a model system we consider a layer of viscous liquid polystyrene (PS) Ω above a viscous liquid substrate consisting of polymethyl methacrylate (PMMA) Ωs. Both liquids are immi scible and the total liquid domain is. Using the functions parametrize the domains at time t h, hs to represent the thickness of fluid and substrate. The substrate layer (PMMA) has a constant thickness hs(t = 0, x, y) = hs and is supported by a solid silicon wafer at z = 0. The contour of the upper liquid layer (PS) is piecewise constant with an almost rectangular edge h (t = 0, x, y) = h for the xe v>o xluc(tito =n 0t)heanddohm (atin=sh0a,pxe, y) = 0 for x ≤ xc(t = 0), which is generated by the preparatio n process.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
