Transpiration Mechanism in Confined Nanopores.

In this work, molecular dynamics simulations show that liquid in a nanopore can be at thermodynamically stable high pressure even when connected to conventional bulk liquid. Such high pressure is associated with strong surface-liquid interaction. Evaporation of liquid in the pore creates a flow from the low pressure (bulk) region to the high pressure (nanopore) region. Such a counterintuitive flow occurs due to pressure being reduced in the pore from its thermodynamically stable state. The transition from high pressures to negative pressures in thin liquid films is also studied. This work provides insight into a possible mechanism of passive liquid transport in tall trees such as redwoods.