The compression of a heavy floating elastic film. Issue 46 (21st October 2016)

• Record Type: Journal Article
• Authors: Jambon-Puillet, Etienne; Vella, Dominic; Protière, Suzie
• Is Part Of: Soft matter. Volume 12:Issue 46(2016)
• Page Start: 9289
• Page End: 9296
• Publication Date: 2016-10-21
• Subjects: Soft condensed matter -- Periodicals; 530.413
• DOI: 10.1039/c6sm00945j
• Languages: English
• ISSNs: 1744-683X

Abstract

Abstract : We study the effect of film density on the uniaxial compression of thin elastic films at a liquid–fluid interface. We show that film density breaks the up-down symmetry that appeared in previous models, and also investigate the behaviour beyond self-contact in the folds. Abstract : We study the effect of film density on the uniaxial compression of thin elastic films at a liquid–fluid interface. Using a combination of experiments and theory, we show that dense films first wrinkle and then fold as the compression is increased, similarly to what has been reported when the film density is neglected. However, we highlight the changes in the shape of the fold induced by the film's own weight and extend the model of Diamant and Witten [ Phys. Rev. Lett., 2011, 107, 164302] to understand these changes. In particular, we suggest that it is the weight of the film that breaks the up-down symmetry apparent from previous models, but elusive experimentally. We then compress the film beyond the point of self-contact and observe a new behaviour dependent on the film density: the single fold that forms after wrinkling transitions into a closed loop after self-contact, encapsulating a cylindrical droplet of the upper fluid. The encapsulated drop either causes the loop to bend upward or to sink deeper as the compression is increased, depending on the relative buoyancy of the drop–film combination. We propose a model to qualitatively explain this behaviour. Finally, we discuss the relevance of the different buckling modes predicted in previous theoretical studies and highlight the important role of surface tension in the shape of the fold that is observed from the side—an aspect that is usually neglected in theoretical analyses.