Aluminium films roughened by hot water treatment and derivatized by fluoroalkyl phosphonic acid: wettability studies

ABSTRACT

Aluminium (Al) films roughened by hot water treatment were used to investigate the impact of their roughness on hydrophobicity upon their derivatization via self-assembled monolayers (SAMs) of a fluoroalkyl phosphonic acid (FPA). Superhydrophobicity was achieved for FPA-derivatized Al films that had been treated in hot water briefly (e.g. 60–180 s), while for prolonged treatment times (e.g. beyond 240 s) degraded hydrophobicity was observed. The observed degradation of hydrophobicity is attributed to surface morphology changes causing water to enter the pores of the roughened Al films. Also studied is the surface chemistry of the FPA SAMs derivatized on Al films, including their thermal stability and a possible mechanism that improves the hydrophobicity. Our results demonstrate that an Al surface immersed in hot water for a couple of minutes generates a porous morphology suitable for rendering superhydrophobicity upon derivatization of the robust FPA SAMs.

KEYWORDS:

• Roughened Al film in hot water
• surface morphology
• surface chemistry
• fluoroalkyl phosphonic acid
• self-assembled monolayers
• superhydrophobicity

Acknowledgement

YMH is grateful to Professor David Shoesmith, the Director of Surface Science Western, for his kind help and encouragement during the visit to the lab.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Heng-Yong Nie http://orcid.org/0000-0002-8287-5171

Additional information

Funding

This work was partially supported by China Scholarship Council and Natural Science Foundation of China (NSFC) [grants number 11564002 and 11764003].