Pinning-depinning of the contact line during drop evaporation on textured surfaces: A lattice Boltzmann study

The evaporation of the liquid droplet on a structured surface is numerically investigated using the lattice Boltzmann method. Simulations are carried out for different contact angles and pillar widths. From the simulation for the Cassie state, it is found that the evaporation starts in a pinned contact line mode. Then, when the droplet reaches the receding state, the contact line jumps to the neighboring pillar. Also, the depinning force decreases with increasing the contact angle or the pillar width. In the Wenzel state, the droplet contact line remains on the initial pillar for all of its lifetime.