Dewetting Nucleation Centers at Soft Interfaces

We study the dewetting of a metastable liquid film, squeezed at a solid/rubber interface, induced by defects printed in the solid glass substrate. We have engraved both protruding (“Mesa”) and depression (“Vickers prints”) defects. For the Vickers prints,we find that a defect of size b dewets films of thickness e < e * =, where h 0 is a microscopic “elastic length” (≈100 Å, defined by the ratio of the liquid spreading parameter S by the elastic modulus E of the soft material). The same behavior is observed for thin Mesa. However, for thick Mesa, the dewetting is limited to the defect area and does not propagate. These results agrees with a theoretical model of nucleation at soft interfaces.