Correlation between surface roughness and hydrophobicity of GLAD RF sputtered PTFE/W/Glass nanorod thin films

In this research, we have used glancing angle deposition (GLAD) RF sputtering technique with various angular speeds ranging from 5 to 30 RPM to fabricate polytetrafluoroethylene (PTFE, Teflon) coated Tungsten on glass substrate for producing hydrophobic surface. According to scanning electron microscopy (SEM) observations, Tungsten nanorods were formed on the substrate with average diameter and length of about ∼50 nm and 300 nm, respectively. Hydrophobic property of W/Glass and PTFE/W/Glass systems was investigated by water contact angle measurements and we have found that the contact angle varied with the substrate angular speed. Maximum contact angle of 121° was measured for the PTFE/W/Glass system at optimum angular speed of 10 RPM. X-ray photoelectron spectroscopy (XPS) determined surface chemical composition and F/C ratio was obtained at 1.15. Based on our data analysis, both of the investigated systems obey Cassie-Baxter model.