Switchable wetting & flexible SiC thin film with nanostructures

Abstract

In this paper, we present the fabrication of flexible surface-nanostructured silicon carbide (SiC) membrane, whose wettability can be simply tuned from super-hydrophobicity to super-hydrophilicity via the combination of an improved deep reactive ion etching (DRIE) process and KOH wet etching process. The thermal annealing is utilized to reduce the stress of SiC membrane produced by plasma enhanced chemical vapor deposition (PECVD) process. High-dense SiC nano-balls are fabricated by the improved DRIE process via the passivation enhancement. Resulting from both the minimized liquid-solid contact area and the fluorocarbon layer atop deposited during the DRIE process, the SiC film with nano-balls shows a reliable superhydrophobicity. Furthermore, after the removal of silicon substrate by KOH wet etching, the flexible SiC membrane with nano-tips is realized, and the wetting behavior switches to superhydrophilicity. The static contact angle (CA) remarkably achieves more than 160 o and less than 1 o , respectively.

Thermal-induced transformation of wetting behaviors on laser-textured SiC surfaces

“…Superhydrophilicity and superhydrophobicity can be tuned by the surface physical and chemical modifications [9,10]. Besides, surface wettability can be reversibly transitioned between hydrophobic and hydrophilic states by altering the pH of the test solution from 12 to 2 as reported by Wan et al [11].…”

“…Transformation of surface wetting behaviors has been widely studied under various conditions, including a range of surface modifications, solution pHs, light irradiation and so on [9][10][11][12][13][14]. Superhydrophilicity and superhydrophobicity can be tuned by the surface physical and chemical modifications [9,10].…”

Effect of droplet size on wetting behavior on laser textured SiC surface

“…Wan et al [11], Zhang et al [12] and Liu et al [13], Kietziga et al [14] all studied the wettability transformation under different experimental conditions, such as pH value, surface morphology, UV illumination and * Corresponding author. Tel.…”