The effect of surface wrinkles on the properties of water in graphene slit pores

Wrinkles are inevitable on the surface of graphene. It leads to changes in the properties of water in graphene slit pore. We investigated how surface wrinkles influence the structure and behaviour of water in graphene slit pores by molecular simulation. Our results show that structure and behaviour of water are influenced by pore width and surface roughness type. With the increase of pore width, the influence of roughness becomes weaker. Due to surface wrinkles, highly-ordered arrangements like square or diamond structure appear in 7 angstrom rough slits. This is the first work where highly-ordered water structure is found in slit pores under normal temperature and pressure. Wrinkles strengthen hydrogen bonding network, but it doesn't always increase the number of hydrogen bonds, which depends on pore width and surface roughness type. The diffusion coefficient significantly decreases in wrinkled slit pores along X-Y plane. Surprisingly, the diffusion coefficient of water in non-rough direction in 9 angstrom wide slit with parallel wrinkles (9(par)) even exceeds that in 9 angstrom wide pristine slit. The number of hydrogen bonds in 9(par) is also very special. This work would further contribute to the design of directional transport of water in wrinkled graphene slit pore.