Water slippage on hydrophobic nanostructured surfaces: molecular dynamics results for different filling levels

Structured hydrophobic surfaces may present high wall slippage due to the microscopic details of wetting. This behavior can be exploited for reducing wall slippage in micro- and nanofluidic devices. In this work we focus on the influence of meniscus curvature and pressure on the slip length. We use realistic atomistic potentials in order to simulate liquid water (TIP4P/2005) flowing on a smooth/patterned silane (OTS) coated hydrophobic surface. Results confirm that even at the nanoscale the form of the meniscus has a strong influence on slippage. Continuum Navier-Stokes simulations show good agreement with the atomistic picture only if the shape of the meniscus and position of the triple line are correctly prescribed.