Open Access Original article

Diatom attachment inhibition: limiting surface accessibility through air entrapment

Alex H-F Wu, Kenichi Nakanishi, KL Cho and Robert Lamb*

Author Affiliations

School of Chemistry, University of Melbourne 3010, Melbourne, Australia

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Biointerphases 2013, 8:5  doi:10.1186/1559-4106-8-5

Published: 7 February 2013

Abstract

Surfaces consisting of sub micron holes (0.420-0.765 μm) engineered into nanoparticle (12 nm) coatings were examined for marine antifouling behaviour that defines early stage settlement. Immersed surfaces were found to be resistant to a 5-hour attachment assay of Amphora coffeaeformis, a marine organism commonly found in abundance on fouled substrates such as foul-releasing paints and self-polishing coatings. Attachment inhibition was attributed to the accessibility of diatoms to the surface. This was governed by the size and morphology of trapped interfacial air pockets measured in-situ using synchrotron small angle x-ray scattering. Surfaces containing larger pores (0.765 μm) exhibited the highest resistance. Macroscopic wettability via contact angle measurements however remained at 160° and sliding angle of < 5° and was found to be independent of pore size and not indicative of early stage fouling behaviour. The balance of hierarchical nano/micro length scales was critical in defining the early stage stability of biofouling character of the interface.

Keywords:
Superhydrophobic; Biofouling; Attachment-inhibition; Diatom; Amphora coffeaeformis; Air-entrapment