Viscoelastic thin polymer films under transient residual stresses: two-stage dewetting on soft substrates.
A nonmonotonic, two-stage dewetting behavior was observed for spin coated thin viscoelastic polymer films on soft elastic substrates. At times shorter than the relaxation time of the polymer (t<tau_{rep}), dewetting generated deep trenches in the soft rubbery substrate which, in turn, almost stopped dewetting. At later stages (t>>tau_{rep}), dewetting accelerated, accompanied by an unstable rim. However, holes nucleated at t<tau_{rep} showed only this second-stage behavior. Our observations are attributed to large elastic deformations in the substrate caused by transient residual stresses within the film.
Institute de Chimie des Surfaces et Interfaces, UHA-CNRS, 15, rue J. Starcky, 68057 Mulhouse Cedex, France.
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Al Akhrass
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Reiter
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