Applied Surface Science, Vol.341, 92-99, 2015
Wettability properties of PTFE/ZnO nanorods thin film exhibiting UV-resilient superhydrophobicity
In this research, initially anodization process was used to fabricate ZnO nanorods on Zn substrate and then RF sputtering technique was applied to grow a thin layer of polytetrafluoroethylene (PTFE, Teflon) on the coated ZnO nanorods for producing a superhydrophobic surface. According to scanning electron microscopy (SEM) observations, ZnO nanorods were formed with average diameter and length of about similar to 180 nm and 14 mu m, respectively. Superhydrophilic property of ZnO nanorods and superhydrophobic property of PTFE/ZnO nanorods was investigated by water contact angle (WCA) measurements. It was found that the contact angle varied with the PTFE deposition time. The highest contact angle measurement was obtained at 160 degrees for the PTFE (60 min coating)/ZnO as optimum sample which indicates its superhydrophobic property. X-ray photoelectron spectroscopy (XPS) determined surface chemical composition and F/C ratio of about 1.27 for this sample. A change of water contact angle from 3 degrees to 160 degrees indicates transition from superhydrophilic to superhydrophobic state. Very low contact angle hysteresis (CAH) of similar to 2 degrees and sliding angle (SA) of similar to 1 degrees as well as unchanged contact angle under UV illumination was observed for the synthesized optimum PTFE/ZnO sample exhibits an excellent superhydrophobic property. Based on our data analysis, the ZnO nanorods and the PTFE/ZnO nanorods obey Wenzel and Cassie-Baxter model, respectively. (C) 2015 Elsevier B.V. All rights reserved.