A facile method for fabrication of superhydrophobic surface with controllable water adhesion and its applications

- Superhydrophobic surfaces were successfully fabricated via alkaline etching method.
- The adhesion force between water droplets and the surfaces of specimens were researched in detail.
- The as-prepared specimens showed excellent durability and chemical stability.
- The applications of specimens in drug delivery, self-cleaning and anti-corrosion were researched quantitative.

In this work, a simple alkaline etching method was presented to fabricate superhydrophobic surfaces. X-Ray Diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and atomic force microscope (AFM) were utilized to characterize the surfaces. The morphology of superhydrophobic surfaces shows hierarchical structures and the corresponding water contact angles (WCA) are more than 155°. The adhesion force between the water droplets and the surfaces were discussed in detail, the specimen etching for 40 min in NaOH solution shows the lowest adhesion. The applications of these superhydrophobic surfaces were exploited. For instance, the superhydrophobic surface with high adhesion can be used in drug delivery. In addition, the self-cleaning property of the superhydrophobic surface with low adhesion was also tested by applying nano-silica powder as dust on the surfaces. Importantly, the superhydrophobic surfaces show excellent anti-corrosion performance with an extremely low corrosion current density of 2.748 × 10−9 A/cm2, and the anti-corrosion mechanism was discussed comprehensively. The present method can also be used to fabricate large-scaled superhydrophobic surfaces and expand applications of metal materials.

Superhydrophobic surface was successfully fabricated on mild steel via alkaline etching method and afterward modified by myristic acid. The adhesion force between water droplets and the surfaces of specimens can be controlled by the etching time. This surface can be used in many fields such as drug delivery, self-cleaning and anti-corrosion.293