Low Density Interior in Supercooled Aqueous Nanodroplets Expels Ions to the Subsurface

The interaction between water and ions within droplets plays a key role in the chemical reactivity of atmospheric man-made aerosols. Here we report direct computational evidence that supercooled aqueous nanodroplets lower density core tetrahedrally coordinated expels cosmotropic to denser more disordered subsurface. In contrast, at room temperature, depending on nature ion radial distribution droplet is nearly uniform or elevated towards center. We analyze spatial single terms reference electrostatic model. energy system analytical model expressed as sum surface deformable droplet. predicts subject harmonic potential centered droplet's center mass. name this effect "electrostatic confinement". model's predictions are consistent with simulation findings for temperature but not supercooling. anticipate study be starting point investigating structure (electro)sprayed used preserve conformations macromolecules originating from bulk solution.