Capillary origami: Spontaneous wrapping of a droplet with an elastic sheet

C.Py, P. Reverdy, L. Doppler, J. Bico, B. Roman, and C.N. Baroud
Physical Review Letters 98, 156103 (13 April 2007).

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The interaction between elasticity and capillarity is used to produce three-dimensional structures through the wrapping of a liquid droplet by a planar sheet. The final encapsulated 3D shape is controlled by tailoring the initial geometry of the flat membrane. Balancing interfacial energy with elastic bending energy provides a critical length scale below which encapsulation cannot occur, which is verified experimentally. This length is found to depend on the thickness as h^{3/2}, a scaling favorable to miniaturization which suggests a new way of mass production of 3D micro- or nanoscale objects