A metallic anti-biofouling surface with a hierarchical topography containing nanostructures on curved micro-riblets

Taekyung Kim; Sunmok Kwon; Jeehyeon Lee; Joon Sang Lee; Shinill Kang

doi:10.1038/s41378-021-00341-3

A metallic anti-biofouling surface with a hierarchical topography containing nanostructures on curved micro-riblets

Microsyst Nanoeng. 2022 Jan 10:8:6. doi: 10.1038/s41378-021-00341-3. eCollection 2022.

Authors

Taekyung Kim¹, Sunmok Kwon^{1

2}, Jeehyeon Lee^{1

2}, Joon Sang Lee^{1

2}, Shinill Kang^{1

2}

Affiliations

¹ National Center for Optically-assisted high precision Mechanical Systems, Yonsei University, Seoul, 03722 Korea.
² School of Mechanical Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 03722 Korea.

Abstract

Metallic surface finishes have been used in the anti-biofouling, but it is very difficult to produce surfaces with hierarchically ordered structures. In the present study, anti-biofouling metallic surfaces with nanostructures superimposed on curved micro-riblets were produced via top-down fabrication. According to the attachment theory, these surfaces feature few attachment points for organisms, the nanostructures prevent the attachment of bacteria and algal zoospores, while the micro-riblets prohibit the settlement of macrofoulers. Anodic oxidation was performed to induce superhydrophilicity. It forms a hydration layer on the surface, which physically blocks foulant adsorption along with the anti-biofouling topography. We characterized the surfaces via scanning electron and atomic force microscopy, contact-angle measurement, and wear-resistance testing. The contact angle of the hierarchical structures was less than 1°. Laboratory settlement assays verified that bacterial attachment was dramatically reduced by the nanostructures and/or the hydration layer, attributable to superhydrophilicity. The micro-riblets prohibited the settlement of macrofoulers. Over 77 days of static immersion in the sea during summer, the metallic surface showed significantly less biofouling compared to a surface painted with an anticorrosive coating.

Keywords: Anti-biofouling; Hierarchical topography; Metallic engineered surface; Nanoimprinting, static immersion test, field trials; Superhydrophilic.