Investigation of water repellency of polytetrafluoroethylene surface by plasma etching

Fabrication of superhydrophobic surfaces (SHS) is important in many fields owing to their excellent advantages such as anti-freezing, corrosion prevention, and self-cleaning. However, to modify the surface structure, environmental pollution caused by complex processes and chemical treatment must be considered. In this study, the surface of polytetrafluoroethylene (PTFE) was plasma-treated using oxygen and argon to change the surface structure without a complicated process. The PTFE surface was treated in two ways: plasma etching (PE) and reactive ion etching (RIE). The contact angle of the pristine PTFE surface was 113.8±1.4°, but the contact angle of the surface manufactured by PE and RIE was 152.3±1.7° and 172.5±1.2°, respectively. The shape of the liquid collision was observed, and the water repellency was confirmed by calculating the contact time. The contact time of the PE specimen was 24 ms longer than that of the RIE specimen, and the RIE specimen was only 18 ms. When the self-cleaning effect was confirmed using graphite, the RIE specimen exhibited an excellent self-cleaning effect, and most of the graphite on the surface was removed within 20 s. We believe that the SHS fabricated by plasma etching method using safe gases can be a good candidate to develop tip-like polymer nanoarrays with special performances in a simple process.