Capillarity-driven Transformation of Microscopic Cellular Structures

Cellular structures are attracting increasing interest because of their unique mechanical, thermal, electrical, and acoustic properties, which largely depend on their size, shape and topology. As such, systems with tunable functionality can be constructed by tuning the geometry of the structures. Here we report a capillarity-driven transformation on 2D onsite microcellular structures that enables us to change their topology on demand and reversibly. To trigger such transformation both the cellular structure and the material have to be carefully designed, as it requires the formation of capillary menisci upon solvent evaporation at the unit-cell scale as well as the softening and stiffening of the material at the molecular scale. Finally, we show that our strategy can be applied to realize surface with tunable properties including adhesion, friction, hardness, and particle trapping.