Abstract:

The structure and dynamics of confined water in cylindrical pores have been investigated by molecular dynamics simulations. Both rigid (TIP4P) and flexible (BJH) models have been used. Pore radii between 4.2 and 20 Å have been studied; the pore walls are modeled either as a smooth (10−4) Lennard-Jones wall or as a structured wall consisting of (12−6) Lennard-Jones particles. Polar functional groups on the pore surface are modeled by arrays of point charges. We present results on density and orientational distribution functions and on the water mobility. We observe that water transport through nonpolar pores is fast and dominated by the surface layer, whereas transport in polar pores is slowed down relative to bulk liquid water and occurs preferentially through the center of the pore.