Under molecular-scale confinement, water exhibits pronounced layered structures accompanied by periodic solid-liquid phase transitions as the channel height $h$ varies. However, the influence of temperature on such periodic phase behavior still remains poorly understood. In this work, we employed extensive molecular dynamics simulations to investigate how temperature (200–400 K) modulates these periodic transitions at medium ($1.0\mathrm{g}/\mathrm{c}{\mathrm{m}}^3$) and high ($1.4\mathrm{g}/\mathrm{c}{\mathrm{m}}^3$) densities with $h$ ranging from $7–15\AA$. We reveal that, compared to ambient temperature, low temperatures enable the formation of multiple ice structures, including trilayer puckered ice, bilayer square-tube ice, and bilayer mixed hexagonal ice. These ice structures are exhaustively characterized through multiple physical quantities (potential energy, diffusion coefficient, lateral pressure), density profiles, lateral radial distribution functions, hydrogen bond distributions and two-dimensional structure factors. By constructing previously unreported $T\text{−}h$ phase diagrams at medium- and high-density respectively, we determine that low temperatures can generate, stabilize, and expand ice phase regions by introducing the aforementioned ice structures, without altering the periodic phase transition pattern. Under high temperature impacts, we surprisingly find that the monolayer and bilayer ice regions at high-density can extend up to 400 K, with minimal loss of ice-phase regions. We attribute this to the fact that the strong confinement effect far outweighs thermal destabilization.

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• Interface & surface thermodynamics
• Nanofluidics
• Phase transitions
• Liquid-solid interfaces
• Water