Effect of Interfacial Dipole on Heterogeneous Ice Nucleation

TL;DR

This study uses molecular dynamics simulations to explore how interfacial dipole strength and orientation influence heterogeneous ice nucleation, emphasizing the importance of molecular orientation similarity over lattice match.

Contribution

It introduces the concept that molecular orientation similarity at interfaces is crucial for ice nucleation, extending the traditional lattice match paradigm.

Findings

Ice nucleation occurs only when interfacial water molecules align with cubic ice.

Improper dipole strength/orientation creates free energy barriers preventing nucleation.

Molecular orientation similarity is key to ice formation, beyond lattice matching.

Abstract

In this letter, we performed molecular dynamics simulations of ice nucleation on a rigid surface model of cubic zinc blende structure with different surface dipole strength and orientation. It follows that, despite the excellent lattice match between cubic ice and substrates, the ice nucleation happened only when the interfacial water molecules (IWs) have the same or similar orientations as that of the water molecules in cubic ice. The free energy landscapes revealed that, for substrates with improper dipole strength/orientation, large free energy barriers arose to prevent the dipole of IWs rotating to the right orientation to trigger ice formation. Our results suggest that the traditional concept of lattice match, the similarity of lattice length between a substrate and the new-formed crystalline, should be extended to a broader match include the similarity between the molecular orientations of the interfacial component and the component in the specific new-formed crystalline face.