Microscopic mechanism of ice nucleation: The effects of surface rough structure and wettability

Abstract

It is significant to inhibit the formation of ice on solid surface under some occasions in industry. The origin of ice formation on solid surface is the heterogeneous ice nucleation, which has drawn a lot of research attention in the last decade. In this work, we investigated the effects of surface fraction, pillar height, and solid surface wettability on ice nucleation using molecular dynamics simulation. Compared with that of smooth surface, the ice nucleation rates on rough surface can be enhanced or inhibited depending on the groove size, which can be attributed to the status of water molecules confined between pillars. In addition, it is found that the ice nucleation rate can be significantly weakened by reducing the solid surface free energy. More importantly, when the surface free energy is low enough, a quenching-induced mobility of nanodroplet is observed, including wandering on the solid surface or jumping away. These findings can address the importance of the coupling effect of the gap width and height of pillars, together with the quenching-induced mobility, which we believe will be helpful to understand more molecular mechanisms of heterogeneous ice nucleation.