Motion behaviour of water-droplet on alternate superhydrophobic/hydrophilic ZnO wetting-patterned surface

ABSTRACT

The wetting-patterned surfaces with alternate superhydrophobicity and hydrophilicity were designed and prepared by a facile solution growth of ZnO nanorods on selectively masked ZnO nanocrystals. The as-prepared patterned film was characterized by SEM; its wetting behaviour was evaluated using a contact angle measuring device. The ZnO-patterned film is composed of hydrophilic ZnO nanograins with a water contact angle of ∼32° and superhydrophobic ZnO nanorod arrays with a contact angle of ∼154°. From the observation of motion behaviour of water-droplets on the patterned films, the static water-droplet on the interface between superhydrophobic and hydrophilic regions moves towards the hydrophilic region in a self-driving way. The motioning water-droplets bypass the superhydrophobic region and then move to the hydrophilic region, even though the latter has a stronger adhesion resistance than the former. Such self-driving and bypassing behaviour can be attributed to their different surface tensions on the superhydrophobic/hydrophilic interface.

KEYWORDS:

• Wetting-patterned film
• ZnO nanomaterials
• superhydrophobicity
• hydrophilicity
• motion behaviour
• water-droplet

Acknowledgements

The authors would like to thank Professor Yuan Zhihao and Dr Qi Gaocan for guidance on paper writing. Authors also thank other colleagues in the research group for extensive discussions.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

N’dri Dieudonné Diby http://orcid.org/0000-0001-6607-4297