  A drop rebounding from a hydrophobic and chemically heterogeneous surface is
investigated using the multiphase lattice Boltzmann method. The behaviors of
drop rebounding are dependent on the degrees of the hydrophobicity and
heterogeneity of the surface. When the surface is homogeneous, the drop
rebounds vertically and the height is getting higher and higher with increases
of the surface hydrophobicity. When the surface consists of two different
hydrophobic surfaces, the drop rebounds laterally towards the low hydrophobic
side. The asymmetrical rebounding is because the unbalanced Young's force
exerted on the contact line by the high hydrophobic side is greater than that
by the low hydrophobic surface. A set of contours of momentum distribution
illustrate the dynamic process of drop spreading, shrinking and rebounding.
This work promotes the understanding of the rebound mechanism of a drop
impacting the surface and also provides a guiding strategy for precisely
controlling the lateral behavior of rebounding drops by hydrophobic degrees and
heterogeneous surfaces.
