  We explore the Casimir-Lifshitz free energy theory for surface freezing of
methane gas hydrates near the freezing point of water. The theory enables us to
explore different pathways, resulting in anomalous (stabilising) ice layers on
methane hydrate surfaces via energy minimization. Notably, we will contrast the
gas hydrate material properties, under which thin ice films can form in water
vapor, with those required in the presence of liquid water. It is predicted
that methane hydrates in water vapor near the freezing point of water nucleate
ice films but not water films.
