| Understand the role of roughness of the surface in suppressing the ice formation is of critical importance in the design of ice-free nanostructured surfaces. While recent work has provided some insight to the design of superhydrophobic surfaces for deicing applications, yet it is not clear that having roughness leading to hydrophobicity itself is good enough for the smart design of ice-free nanostructure surface; or should there be more careful construction of such surfaces. Further, recent experiments also suggest that even hydrophilic surfaces can be used for deicing applications. Hence, it is not clear what causes the major effect i.e., is it “hydrophobicity/ hydrophilicity” or “surface textured geometry”? In addition, various questions are still to be answered convincingly such as the effect of surface texture and its hierarchical nature on the relaxation or dynamics of the supercooled liquid phase. In this work, we have investigated the behaviour of supercooled water on smooth and rough surfaces using extensive molecular dynamics. Roughnesses of the order of 1-2 nm are created on a graphite like surface. Water is modeled as monatomic water model, which has recently been used intensively. In particular, we present the role of surface fraction (fraction of solid on the interface) and roughness on the onset of crystallization while cooling from 270 K to 190 K with a cooling rate of 0.5-1K/ns. We also present, in detail, ice cluster growth process and ice phases as observed for different rough surfaces. |
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