Accelerated chemical reactions with surface nanodroplets
The compartmentalization of chemical reactions within droplets has advantages in low costs, reduced consumption of reagents and increased throughput. Reactions in small droplets have also been shown to greatly accelerate the rate of many chemical reactions. In this talk, we will first introduce a simple continuous approach for the formation of multicomponent nanodroplets from a nucleation-growth process. Then we will show that growth rate of nanobubbles from reactions at nanodroplet surface depends on the droplet size. The gaseous products from the reaction at the nanodroplet surface promoted nucleation of hydrogen nanobubbles within multiple organic liquid nanodroplets. The growth rate of the bubbles was significantly accelerated within small droplets and scaled inversely with droplet radius. The acceleration was attributed to confinement from the droplet volume and effect from the surface area on the interfacial chemical reaction for gas production. In a second model system, we show how the rate for biphasic chemical reactions between acidic nanodroplets and basic reactants in a surrounding bulk flow is influenced by the droplet size and the flow conditions. The reaction rate is measured by droplet shrinkage as the product is removed from the droplets by the flow. In this way we can determine the dependence of the reaction rate on the flow rate and the solution concentration. The experimental results reflect the collaborative effect from neighboring droplets. The results of this study may provide some insights into in droplet enhanced production for the ultimate aim to enhance droplet reactions under flow conditions.