Infusing paraffin-based lubricant into micro-/nanostructures for constructing 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. Herein, 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 crystallized and nucleated through a phase transition by temperatures to reduce the rheological properties of the lubricant and improve its stability. 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. This 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.