Antithetic superhydrophobic/superhydrophilic surfaces formation by simple gas switching in an atmospheric-pressure cold plasma treatment

The wettability control of surfaces is a significant issue in many industrial fields such as encapsulation, water repellency enhancement, oil recovery, etc. From a practical point of view, to reach the intended surface wettability, it is important for a surface modification process to be low-cost, easily implemented and fast. Therefore, in this work, a facile plasma deposition method is suggested to form surfaces with antithetic wettabilities, i. e. superhydmphobic and superhydrophilic, via simple introduction of additive gases in an atmosphericpressure plasma generated with argon and hexamethyldisilazane (HMDS). The hydrophobic surface (WCA: 115 degrees) modified by Ar/HMDS plasma is easily switched to superhydrophobic surface (WCA: 1601 by N-2 addition and to superhydmphilic surface (WCA: 10 degrees) by O-2 addition. From physical and chemical analyses of plasma treated surfaces, a small amount of N-2 or O-2 gas is shown to dramatically change the surface morphology and chemical composition. Besides, by finely tuning the additive gases flow rates, the surface wettability could be continuously modulated in the whole similar to 0 degrees to 160 degrees water contact angle range.

Automated summary

The control of surface wettability is crucial in various industrial fields, and a facile plasma deposition method is suggested in this work to achieve superhydrophobic and superhydrophilic surfaces by introducing additive gases. The addition of a small amount of N-2 or O-2 gas can dramatically change the surface morphology and chemical composition, allowing for continuous modulation of surface wettability.