Nearly Perfect Durable Superhydrophobic Surfaces Fabricated by a Simple One-Step Plasma Treatment

Abstract

Fabrication of superhydrophobic surfaces is an area of great interest because it can be applicable to various engineering fields. A simple, safe and inexpensive fabrication process is required to fabricate applicable superhydrophobic surfaces. In this study, we developed a facile fabrication method of nearly perfect superhydrophobic surfaces through plasma treatment with argon and oxygen gases. A polytetrafluoroethylene (PTFE) sheet was selected as a substrate material. We optimized the fabrication parameters to produce superhydrophobic surfaces of superior performance using the Taguchi method. The contact angle of the pristine PTFE surface is approximately 111.0° ± 2.4°, with a sliding angle of 12.3° ± 6.4°. After the plasma treatment, nano-sized spherical tips, which looked like crown-structures, were created. This PTFE sheet exhibits the maximum contact angle of 178.9°, with a sliding angle less than 1°. As a result, this superhydrophobic surface requires a small external force to detach water droplets dripped on the surface. The contact angle of the fabricated superhydrophobic surface is almost retained, even after performing an air-aging test for 80 days and a droplet impacting test for 6 h. This fabrication method can provide superb superhydrophobic surface using simple one-step plasma etching.

Recent Advances in Surface Activation of Polytetrafluoroethylene (PTFE) by Gaseous Plasma Treatments

“…SEM was used to reveal the topography. It was similar to that reported by Ryu et al [ 19 ] except that the aspect ratio of the nanostructures was over 10. The ion radiation time was of the order of a minute.…”

“…Ryu et al [ 19 ] also used the Ar–O 2 mixture and found similar results as Carbone [ 17 ] except that the increased hydrophobicity was even more pronounced. They used a low-pressure gaseous plasma generated by a capacitively coupled radiofrequency discharge.…”

“…The effect of the incidence angle was less pronounced for 800 eV ions. Interestingly, no WCA above 150° was reported by Pachchigar et al [ 20 ], although the surface topography was exceedingly abundant, even more than what was reported by Ryu et al [ 19 ].…”

“…The super-hydrophobic character remained almost unchanged even after 80 days. The plasma parameters of a capacitively coupled radiofrequency discharge (CCP) adopted by Ryu et al [ 19 ] are entirely different from the ones of MW discharge used by Carbone [ 17 ]. Namely, low-pressure CCP is characterized by the significant kinetic energy of positively charged ions, as well as the extensive radiation of O atoms at about 130 nm, which is in the VUV range [ 12 ].…”

Hydraulic Strategy of Cactus Trichome for Absorption and Storage of Water under Arid Environment

“…As a trichome-inspired hydrophobic membrane, a polytetrafluoroethylene (PTFE) mesh (APEC Ltd., Korea) was selected for surface modification via plasma treatments, and a polyamide mesh (APEC Ltd., Korea) was used as a control model. By employing plasma treatment (Ryu et al, 2017 ) on the mesh, the surface of PTFE was modified to nearly superhydrophobic surface with a contact angle of ~149°. The surface morphology of the hydrophobic mesh was modified by plasma etching using Ar and O 2 gases.…”