Dynamical behavior of an evaporating nanomeniscus: A boundary condition problem at the local scale

Evaporation processes are a common feature in micro and nanofluidics where aqueous solutions are employed. Evaporation can be used as the driving phenomenon to control laminar flows in microchannels. The present analysis shows intricate phenomena, leading to opposite effects, induced by the thinning of a nanomeniscus. The viscous dissipation inside the nanomeniscus is the result of a competition between the capillary flow, due to evaporation, enhancing the dissipation and the boundary conditions at the air-liquid interface reducing the influence of the shear motion in the meniscus. Simple hydrodynamic arguments show how macroscopic concepts can apply to explain the dynamical behavior of a very small quantity of an oscillating liquid. © Europhysics Letters Association