Elasticity and damping ratio measurement of droplets on super-hydrophobic surfaces

The elasticity of the droplet refers to the ability of the droplet in
restoring to its original shape and ensuring its strong robustness. The
measurement of the droplets' elasticity is vitally important in
understanding the characteristics and mechanism of the droplet jumping,
spreading, and coalescence. In this paper, we measured the elasticity and
damping ratio of droplets with different viscosity. A plate coated with a
hydrophobic layer pressed on a droplet, and the elastic force was recorded
by an electronic balance. Meanwhile, a mathematical model was constructed
to illustrate the change rate of the droplet area with the elastic force.
By comparing the influence of volume and viscosity on elasticity, the
results showed that work done by pressure converts into surface energy.
And the elasticity of the droplet is provided by the surface tension and
the damping ratio increases from 0.068 to 0.261.