Effective Control of Thermal Transfer in Nanoconfined Water by Applying an Electric Field: A Molecular Dynamics Study.

Thermal properties of water confined at the nanoscale exhibit variations compared with bulk water. The dynamics of water molecules is altered when an electric field is applied, which influences the thermal transport in nanoconfined water. To explore this phenomenon, we conducted molecular dynamics simulations to investigate the thermal transport of confined water in nanochannels under a uniform electric field. The findings indicate that the thermal conductivity of nanoconfined water decreases when the electric field strength is below 4 V nm^-1 in the direction parallel to the solid-liquid interface of the nanochannel or below 9 V nm^-1 in the direction perpendicular to the solid-liquid interface. This decrease can be attributed to the limited thermal diffusion of water molecules caused by the electric force. On the contrary, when the electric field strength surpasses 4 V nm^-1 or 9 V nm^-1, the thermal conductivity of nanoconfined water experiences a substantial increase due to the freezing of water molecules induced by the strong electric field. The interfacial thermal resistance decreases on the heat source side, while it increases with increasing electric field strength on the cold source side. Furthermore, applying an electric field parallel to the nanochannel facilitates the electro-freezing of water molecules more effectively, resulting in a greater enhancement of thermal transport in nanoconfined water.