Induced Charge Density and Thin Liquid Film at Hydrate/Methane Gas Interfaces

The hydrate/methane gas interface is studied by molecular dynamics simulations. Below the hydrate melting temperature a thin liquid film forms with an associated surface charge density and electrostatic potential. The thickness of the thin liquid film, the charge density, and electrostatic potential at the hydrate/gas interface are established at different subcooling temperatures for the first time. The hydrate interface has mixed polarity, being predominantly positive. A comparison is made with the ice/ methane interface, which reveals similarities and differences in the induced charge density. The thin liquid film and the induced charge density have important implications for the interfacial properties of methane hydrates.