Oleic acid-modified superhydrophobic ZnO nanostructures via double hydrothermal method

Abstract

Superhydrophobic ZnO nanostructures (ZNs) are synthesized via double hydrothermal method without any surface chemical modification. The water contact angle (CA) was approximately ∼150 ± 2°. A subsequent chemical treatment with oleic acid (OA) contributed to a superhydrophobic surface with a water CA of 162 ± 2°. X-ray diffraction pattern revealed high crystalline quality ZNs with hexagonal wurtzite phase. The crystallite size was approximately ∼23 nm. Field-emission scanning electron microscopy images display nanosheet formations assembled in flower-, cauliflower-, and nanorod-like ZNs. The CA of ZNs surfaces increased steadily from 152 ± 2° to 162 ± 2° when the OA weight percentage increased from 2 mg to 10 mg. Furthermore, UV–Vis spectra of ZNs indicated that the absorption band of all samples is distinguished in the ultraviolet region. All ZnO samples were maintained at room temperature for 1 h to 5 months to examine the stability of the structure surface.

Keywords:

• Superhydrophobic surfaces
• ZnO
• nanostructures
• oleic acid
• Surface modification
• double hydrothermal method

Acknowledgments

The authors are grateful for the financial support received for this work from the Department of Physics, College of Science, Mustansiriya University, Baghdad, Iraq.

Disclosure statement

No potential conflict of interest was reported by the authors.