On complete rebound of liquid droplets impacting on soft hydrophobic surfaces

With the method of high-speed camera and image recognition, the complete rebound of the liquid droplet with different viscosity impacting on the surface of the soft hydrophobic material (PDMS) with different elastic modulus was obtained. The influence curves of liquid viscosity and PDMS elastic modulus on the rebound Weber number and recovery coefficient of the droplet were also plotted. Due to the influence of liquid viscosity on the spreading process and viscous energy dissipation, the maximum and minimum Weber numbers of droplet complete rebound on PDMS surfaces increase with the increase of droplet viscosity, and the rebound recovery coefficient gradually decreases. With the decrease of the elastic modulus of PDMS, the maximum Weber number of droplet complete rebound on PDMS surface increases and the minimum Weber number decreases, and the elastic modulus of PDMS has no significant effect on the rebound recovery coefficient.