Fabrication of Hydrophobic Ni Surface by Chemical Etching.

Xiaojing Qian,Junhong Luo,Huan Wang,Changan Chen,Deli Luo,Tao Tang

doi:10.3390/ma12213546

Abstract

Hydrophobic surfaces were successfully fabricated on pure nickel substrates by a one-step chemical etching process with different acidic solutions. The static water contact angle (SCA) of the etched Ni surfaces reached higher than 125°, showing excellent hydrophobicity. The examination of surface chemical compositions implied that there were almost no polar moieties on the surface after chemical etching, except part of the surface was oxidized. After chemical etching, the nickel surfaces became much rough with packed terrace-/crater-/thorn-like clusters. According to the analysis of surface composition and morphology, the hydrophobicity was evidently attributed to the rough microstructures on the etched Ni surface. The best hydrophobicity on Ni surface was produced with the SCAs as high as 140.0° by optimizing the etching time and etchants. The results demonstrate that it is possible to construct hydrophobic surfaces on hydrophilic substrates by tailoring the surface microstructure using a simple chemical etching process without any further hydrophobic modifications by low surface energy materials.

Highlights

Wettability is one of the most important properties of solid surfaces, and depends on both the surface microstructure and the chemical composition [1,2,3]
The wettability the an nickel surface before and after chemical measuring the static water contact angle (SCA) of using optical contact angle instrument
The hydrophobic surfaces on pure nickel substrates were successfully prepared via a one-step chemical etching process without introducing low surface free energy materials

Summary

Introduction

Wettability is one of the most important properties of solid surfaces, and depends on both the surface microstructure and the chemical composition [1,2,3]. Thereby, the hydrophobicity of surface can be tuned by tailoring of surface roughness or adjusting of its surface free energy [4,5,6,7,8,9,10]. The latter method has been usually applied to prepare hydrophobic or superhydrophobic surfaces on metal or alloy substrates which are intrinsically hydrophilic. Most of them have to introduce low surface energy materials in order to obtain the hydrophobic or superhydrophobic surface

Methods

Results

Conclusion