Stabilizing Liquid in Precise Nonequilibrium Shapes via Fast Interfacial Polymerization

Abstract Due to the minimization of interface area caused by surface tension, the stabilization of liquid in complex and precise nonequilibrium shapes is challenging. In this work, a simple, surfactant‐free, and covalent strategy to stabilize liquid in precise nonequilibrium shapes via fast interfacial polymerization (FIP) of highly reactive n‐butyl cyanoacrylate (BCA) monomer triggered by water‐soluble nucleophiles is described. Full interfacial coverage can be achieved instantly, and the resultant polyBCA film anchored at the interface can support the unequal interface stress, which allows the production of non‐spherical droplets with complex shapes. Notably, the formulation of internal aqueous phase is nearly unaffected since no specific additive is required. Moreover, considering the excellent biocompatibility of BCA and polyBCA, the produced droplets can be used as micro‐bioreactor for enzyme catalysis and even bacterial culture, which well mimic the morphology of cells and bacteria to achieve the biochemical reaction in non‐spherical droplets. The present work not only opens a new sight for the stabilization of liquid in nonequilibrium shapes, but may also promote the development of synthetic biology based on non‐spherical droplets, and tremendous potential applications are anticipated.