Elevated melting of hydrogen-disordered ice confined by MoS2 nanotubes: A molecular dynamics study of dual confinement geometries

• Molecular dynamics simulations reveal a ∼30 K increase in the melting point of hydrogen-disordered ice confined between MoS 2 nanotubes. • Melting behavior is governed primarily by hydrogen bond defects and MoS 2 surface interactions rather than being primarily driven by geometrical confinement. • MoS 2 ’s semi-polar hydrophilic surfaces induce distinct melting dynamics compared to hydrophobic carbon nanotubes. • Dual confinement geometries ( inside vs. between nanotubes) enable tunable phase-change behavior with potential applications in cryopreservation and energy storage. While carbon-based nanomaterials have been extensively studied for water confinement, far less is known about the influence of molybdenum disulfide (MoS 2 ) nanotubes on the phase behavior of ice. Using molecular dynamics (MD) simulations, this study unveils how MoS 2 nanotubes, owing to their unique semi-polar, hydrophilic surfaces, significantly affect the stability and melting of hexagonal ice under nanoconfinement. We investigate two distinct confinement modes: (1) within the nanotubes and (2) in the interstitial space between them for both hydrogen-ordered and defect-introduced ice structures. A striking ∼30 K upward shift in melting temperature is observed for defect-introduced ice confined between nanotubes. This effect is absent in comparable carbon nanostructures, highlighting the critical role of defect-introduced ice and surface interactions. Furthermore, we systematically assess the influence of nanotube diameter and heating rate, revealing that melting behavior is dominated more by molecular-level interactions than by geometrical confinement alone. These results demonstrate the novel potential of MoS 2 as a tunable platform for phase-change control, with broad implications for cryopreservation, energy storage, pharmaceuticals, and the design of nanostructured thermal materials.