Slippery marine antifouling coatings

Slippery liquid-infused porous surfaces (SLIPS) have enormous potential to substitute for traditional antifouling coatings due to green broad-spectrum antifouling properties. However, the serious loss of lubricants is a major problem in their applications. Now, anodic aluminum oxides (AAO) with different morphologies were prepared, modified with siloxane and infused with paraffin-based lubricant to explore the lubricant retention capacity of specially-designed AAO. The results showed that pyramid-like cluster structures on the porous surface can offer large space to store more lubricant, forming a barrier to alleviate lubricant loss to a certain extent. Paraffin added to silicone oil crystallised and nucleated through a phase transition by temperatures to reduce the rheological properties of the lubricant and improve its stability.

Broaden the applications of SLIPS

As the researchers point out, the combination of unique surface structures in AAO and the infusion of paraffin-based lubricant can ensure the long-lasting storage and conservation of the lubricant in AAO, moreover, the thermally sensitive paraffin-based framework can quickly switch and the dispersed silicone oil provided liquid-repellency properties. Antifouling tests showed that paraffin-based SLIPS demonstrated a reduced adhesion of the Phaeodactylum tricornutum to 96 % as compared to that of the flat aluminum alloy surface. The work shows that the combination of the geometric features of substrate and the fluid properties of paraffin-based lubricant can broaden the applications of SLIPS in marine antifouling technology.

The study has been published in Progress in Organic Coatings, Volume 185, December 2023.