The hydrophobic properties were achieved for RF-sputtered ultra-thin polytetrafluoroethylene (PTFE) films deposited on silicon surfaces. In our investigation, super-hydrophobic surfaces with water contact angles higher than 90o were achieved on RF-sputtered ultra-thin PTFE films of less than 100 nm coated on silicon surfaces prepared for electrowetting on dielectric (EWOD) applications. The plasma deposition mechanism is discussed in this letter. We analyze here the EWOD principles applied to microfluidic devices which have double hydrophobic layer materials, ZnO and PTFE. We also compared sputter coated polymer with ZnO and InP films using atomic force microscope (AFM). AFM images were measured to correlate the data with surface shapes.