Vibration of water droplet located on a hydrophobic sheet under the tangential AC field

The behavior of a water droplet placed on the surface of the hydrophobic polymer sheet under AC field was investigated experimentally. In order to confirm the effect of hydrophobicity on the movement of the water droplet, two kinds of hydrophobic insulating materials, PTFE and silicone rubber (SR) were used. A single water droplet was placed on the insulating sheet where AC electric field was applied. The frequency of AC voltage was varied from 10 to 100 Hz. The change of the droplet shape during vibration was investigated in detail. The droplet was deformed and synchronized with the AC field. The amplitude of vibration strongly depends on the frequency and the volume of water droplet. It was revealed that water droplet vibrates strongly at a definite frequency and the resonance frequency of a droplet with a volume of 10 /spl mu/l and 30 /spl mu/l is 30 Hz and 22 Hz, respectively.