Robust two-dimensional ice on graphene built from finite-length water molecular chains

TL;DR

This study reveals that 2D ice structures on graphene, formed from finite-length water chains, exhibit strong interlayer interactions and are influenced by the number of graphene layers, challenging previous assumptions of negligible interaction.

Contribution

It provides atomic-resolved evidence of strong water-graphene interactions and links water chain length to graphene layer number, advancing understanding of 2D ice on inert substrates.

Findings

Water molecular chains align along graphene zigzag directions.

Strong interlayer interaction between 2D ice and graphene.

Water chain length depends on graphene layer number.

Abstract

Interfacial ice on graphene has attracted much attention because it is a model system to study two-dimensional (2D) ice structures on chemically inert substrates. While water-graphene interaction was usually assumed to be negligible, the structures of the 2D ice are believed to be not appreciably perturbed by the graphene substrate. Here we report atomic-resolved characterizations of an exotic 2D ice structure on graphene built from water molecular chains with finite lengths. Our experiments demonstrated that the water molecular chains are exactly orientated along zigzag directions of the graphene substrate, which evidences an anomalously strong interlayer interaction between the 2D ice and the graphene substrate. Moreover, the length of the water molecular chains closely links to the number of graphene layers, indicating layer-number-dependent water-graphene interfacial interactions. Our work highlights the important role of the 2D ice structures on the water-graphene interfacial interactions.