6533b827fe1ef96bd1286832
RESEARCH PRODUCT
Capillary Rise in Nanopores: Molecular Dynamics Evidence for the Lucas-Washburn Equation
D. I. DimitrovKurt BinderAndrey MilchevAndrey Milchevsubject
NanotubeMaterials scienceCapillary actionFluid Dynamics (physics.flu-dyn)General Physics and AstronomyFOS: Physical sciencesSlip (materials science)MechanicsPhysics - Fluid DynamicsComputational Physics (physics.comp-ph)Condensed Matter::Soft Condensed MatterPhysics::Fluid DynamicsMolecular dynamicsNanoporeClassical mechanicsWashburn's equationImbibitionVector fieldPhysics - Computational Physicsdescription
When a capillary is inserted into a liquid, the liquid will rapidly flow into it. This phenomenon, well studied and understood on the macroscale, is investigated by Molecular Dynamics simulations for coarse-grained models of nanotubes. Both a simple Lennard-Jones fluid and a model for a polymer melt are considered. In both cases after a transient period (of a few nanoseconds) the meniscus rises according to a $\sqrt{\textrm{time}}$-law. For the polymer melt, however, we find that the capillary flow exhibits a slip length $\delta$, comparable in size with the nanotube radius $R$. We show that a consistent description of the imbibition process in nanotubes is only possible upon modification of the Lucas-Washburn law which takes explicitly into account the slip length $\delta$.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2007-03-30 |