Reconfigurable liquid devices from liquid building blocks

Liquids are widely applied in the construction of various functional devices due to their abilities to flow, dissolve, deform and phase separate; however, the fabrication of liquid-based devices can be costly and lack reconfigurability due to the need for predesigned solid enclosing walls. Herein we report a strategy to generate and manipulate functional liquid devices by assembling and disassembling different types of liquid droplets like toy building blocks; we also uncover the underlying mechanisms. Multiphase liquid devices with diverse compositions and geometries can be quickly constructed and reconfigured in a pillared substrate, enabling the ability to freely structure liquids and precisely program liquid–liquid interfaces. The applications in fluidic devices, microreactors and their combinations are demonstrated. Building liquid devices from solid enclosing walls can be costly and lack reconfigurability. Now the rapid construction and reconfiguration of diverse liquid devices is demonstrated through assembly and disassembly of droplet arrays in a pillared substrate.