Impact on mechanical robustness of water droplet due to hydrophilic nanoparticles

The mechanical robustness of droplets is a crucial factor for many applications. In the present work, we reported that adding a small and certain number of hydrophilic nanoparticles can significantly enhance the mechanical robustness of water droplets. Among the various hydrophilic nanoparticles investigated, SiO2 was found to be the most effective one. Experiments and molecular dynamics simulations were used to understand the physics of the phenomenon. It turned out that the microscopic structure at the solid-liquid interface becomes more ordered compared to the pure liquid droplet due to the interaction between nanoparticles and liquid molecules. This ordered structure can strengthen the solvent-mediated forces between nanoparticles, which, in turn, enhances the solid-like performance of the liquid surface and thus the robustness of the droplet.