Dynamically Reconfigurable Complex Emulsion Droplets as Intelligent Microreactors

Multicompartments in complex emulsions, which mimic the organelles of living cells, can spontaneously sequester reactants/products and confine spatially incompatible compounds. This provides opportunities to control spatiotemporal reaction processes and to be a sustainable and high-efficiency platform for biphasic reactions even under stirring-free and ambient temperatures. We introduce a new multicompartment droplet microreactor based on one-step prepared complex emulsions. An organic/aqueous addition reaction between oil-soluble stilbene and water-soluble N-bromosuccinimide is employed as a model biphasic reaction. The conversion in the proposed complex droplet microreactor achieves a rate about 25 times higher than that in a traditional triphasic batch system. Over a 10 times threshold of the reaction rate is finely tuned by rationally engineering diverse droplet morphologies. Reversible in situ control of the reaction kinetics is achieved based on the reversible topology transition manipulated by the surfactant composition and temperature, with no need for adding any extra substance. Furthermore, reaction kinetics are precisely regulated by the droplet size and the shape of the two inner lobes. After rapid demulsification, over 86% of the target product is spontaneously enriched in one separated phase with a maximum purity of 98% following solvent removal. The byproduct succinimide and the solvent fluorocarbon phase are fully recycled to avoid potential pollution problems.