Energy criteria for elasto-capillary wrapping

We consider the interaction between a liquid drop and a flexible membrane, a fluid-structure problem where capillarity is the dominant fluid contribution. Recent work has shown that surface tension may be used to bend an elastic membrane if the typical scale of the membrane is above a critical length. Here, we discuss some more detailed experimental measurements that demonstrate the switching between different modes of folding as well as a dewetting transition during the folding of the membrane. A model is then developed, based on an energy approach, and shown to account for all of the observed phenomena. Contrary to more refined modelling, the minimal model may be extended to more complex cases with little extra work, making it useful for complex geometries or in order to include further physical ingredients. (C) 2009 Elsevier Ltd. All rights reserved.