Disentangling reaction rate acceleration in microdroplets

We have investigated the origin of the unexpected, recently discovered phenomenon of reaction rate acceleration in water microdroplets relative to bulk water. Acceleration factors for reactions of atmospheric and synthetic relevance can be dissected into elementary contributions thanks to the original and versatile kinetic model. The microdroplet is partitioned in two sub-volumes, the surface and the interior, operating as interconnected chemical reactors in the fast diffusion regime. Reaction rate acceleration and its dependence on reaction molecularity and microdroplet dimensions are explained by applying transition-state-theory at thermodynamic equilibrium. We also show that our model, in combination with experimental measurements of rate acceleration factors, can be used to obtain chemical kinetics data at the air-water interface, which has been a long-standing challenge for chemists.

Automated summary

This study investigates the origin of the unexpected phenomenon of reaction rate acceleration in water microdroplets compared to bulk water. Using a unique and versatile kinetic model, the acceleration factors for atmospheric and synthetic reactions can be broken down into elemental contributions. The microdroplets are divided into surface and interior sub-volumes, acting as interconnected chemical reactors in the fast diffusion regime. The acceleration of reaction rates and its dependence on reaction molecularity and microdroplet dimensions are explained using transition-state theory at thermodynamic equilibrium. Additionally, the study demonstrates that the model, combined with experimental measurements of rate acceleration factors, can be used to obtain chemical kinetics data at the air-water interface, a long-standing challenge for chemists.