Dynamics of three-phase contact line when crossing micro-patterns

Within the Couette flow computational system, the slip behavior of the three-phase contact line as it crosses a micro-pattern was numerically analyzed using a modified interFoam solver shipped with OpenFoam. Micro-patterns are rectangular hydrophilic, hydrophobic, pillar, and hole areas, which are located on a surface with intrinsic contact angle at 60°. The calculation results show that on the hydrophilic area decorated surface, the three-phase contact line is slowed down, and then a shooting behavior is seen when it leaves the pattern. An inverse crossing behavior is obtained on hydrophobic area masked surface. On the surfaces with a micro- pillar or hole, the breaking of the liquid tail enhances the sliding of contact line. The findings in this work will be help for designing functional slippery surfaces.