  We consider a three-dimensional network of aqueous droplets joined by single
lipid bilayers to form a cohesive, tissue-like material. The droplets in these
networks can be programmed to have distinct osmolarities so that osmotic
gradients generate internal stresses via local fluid flows to cause the network
to change shape. We discover, using molecular dynamics simulations, a
reversible folding-unfolding process by adding an osmotic interaction with the
surrounding environment which necessarily evolves dynamically as the shape of
the network changes. This discovery is the next important step towards osmotic
robotics in this system. We also explore analytically and numerically how the
networks become faceted via buckling and how quasi-one-dimensional networks
become three-dimensional.

Soft Condensed Matter