Hydrophobic Aluminum Alloy Surfaces Fabricated by Imprinting Process and Their Wetting State Evaluation Using Air Layer

  • PDF / 3,331,189 Bytes
  • 13 Pages / 595.276 x 790.866 pts Page_size
  • 77 Downloads / 201 Views

DOWNLOAD

REPORT


International Journal of Precision Engineering and Manufacturing https://doi.org/10.1007/s12541-020-00441-6

REGULAR PAPER

Hydrophobic Aluminum Alloy Surfaces Fabricated by Imprinting Process and Their Wetting State Evaluation Using Air Layer Images In Yong Moon1 · Seong‑Hoon Kang1 · Jonghun Yoon2  Received: 30 January 2020 / Revised: 19 October 2020 / Accepted: 12 November 2020 © Korean Society for Precision Engineering 2020

Abstract This paper presents an imprinting process, which can impart hydrophobicity to aluminum alloy surfaces, and a method for analyzing the wetting states of solid surfaces with multi-scale structures. Electrical discharge textured (EDT) surface and groove pattern molds were produced by electrical discharge machining (EDM) and wire electrical discharge machining (WEDM), respectively. The aluminum surfaces having hierarchical patterns were produced by imprinting processes using both EDT surface and groove pattern molds. The groove patterns with various pitches from 400 to 1,000 µm were applied to the mold designs, so that the effects on static water contact angle (WCA) could be analyzed. Results showed that the hydrophobic aluminum surface with WCA of 117.6° can be achieved through the facile imprinting process. In addition, a wetting state analysis method using air layer images was proposed. Using this method, it was demonstrated that the surface wetting state can be accurately analyzed by combining the air layer images and the theoretical models such as the Cassie–Baxter, and Wenzel models. Keywords  Hydrophobic · Imprinting · Hierarchical patterns · Wetting state · Air layer

1 Introduction Water repellent surface is one of the representative functions obtained by nature-inspired technology [1–3]. Typical applications of water repellent surfaces include self-cleaning, drag-reduction, anti-fouling, and oil–water separation [4, 5]. Therefore, water repellent surfaces of various materials have been continuously studied, mainly in the field of micro/nano engineering. As methods for imparting water repellency to targeted solid surfaces, various techniques such as laser ablation [6–10], etching [11, 12], wire electrical discharge Seong-Hoon Kang, Jonghun Yoon have contributed equally * Seong‑Hoon Kang [email protected] * Jonghun Yoon [email protected] 1



Korea Institute of Materials Science, 797 Changwondaero, Seongsangu, Changwon, Gyeongnam 51508, Republic of Korea



Department of Mechanical Engineering, BK21FOUR ERICA‑ACE Center, Hanyang University, 55 Hanyangdaehak‑ro, Sangnok‑gu, Ansan, Kyeonggi‑do 15588, Republic of Korea

2

machining (WEDM) [13–15], and imprinting [16, 17] have been used. In particular, the imprinting process offers great advantages in terms of productivity as it can repeatedly replicate pre-fabricated hierarchical structures of mold surfaces onto a target material surface. In the case of the polymers, if the process temperature is set to above the glass transition temperature of the target material, replication can be easily performed without any undesired mold