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

TL;DR

This paper demonstrates how elastic sheets can spontaneously wrap droplets to form 3D structures, with a model predicting a critical length scale for encapsulation, enabling potential micro- and nano-scale manufacturing.

Contribution

It introduces a 2D model for elastocapillary wrapping and identifies a critical length scale dependent on sheet thickness, advancing understanding of capillary-elastic interactions.

Findings

Experimental verification of the critical length scale for encapsulation.

The elastocapillary length scales as h^{3/2}, favoring miniaturization.

Potential for mass production of micro- and nano-scale 3D objects.

Abstract

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 tayloring the initial geometry of the flat membrane. A 2D model shows the evolution of open sheets to closed structures and predicts a critical length scale below which encapsulation cannot occur, which is verified experimentally. This {\it elastocapillary 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 nano-scale objects.