Investigation of dynamic characteristics of impacting nanodroplets on solid surfaces decorated with a stepped texture

This work mainly focuses on the passive manipulation of the impact dynamics of nanodroplets using superhydrophobic surfaces decorated with a stepped surface via molecular dynamics (MD) simulations. Based on various impact conditions, we observe a series of novel impact dynamics that are quite different from the normal impact on smooth surfaces, mainly including the deflected rebound at the top/base of the stepped surface, and directional transport and splitting of droplets. The reason why the stepped texture can produce these fascinating dynamic characteristics is detailly investigated by calculating the centroid coordinate, free energy, and spread factor variations. The asymmetric dynamics of impacting droplets on stepped surfaces should be the primary reason for observed phenomena. The phase diagram is established to obtain overall insights into the impacting dynamics. This work can pave the way to assist practical applications, which require manipulating droplets at the nanoscale.