SLIPS against drag

Slippery-liquid infused porous surfaces (SLIPS) have provided a new research direction in bioinspired materials. These composite materials are obtained starting from a micro/nanostructured surface, metallic or polymeric, in which an appropriate lubricant fluid is infused. The lubricant penetrates into the surface pores and is trapped by the surface morphology. In the present study SLIPS are examined in light of their possible use for drag reduction in naval applications; in fact, the interface with the seawater is mainly due to the infused liquid, inducing a relevant drag reduction. The paper reports a method for the preparation of a SLIPS starting from 1000 series aluminum plates of about 20 cm2, i.e., in lab scale; then, its characterization in terms of anticorrosion properties by EIS and anti-drag performances by rheometric tests is reported. In addition, the attempt to realize larger-scale SLIPS is described; the specimen was a 3 m2 panel, analyzed to determine its anti-drag performance in a towing tank. In lab scale the SLIPS did not yield anti-corrosion properties, but the drag reduction was about 14%. In the towing tank it was possible to discriminate the drag resistance of the SLIPS with respect to a standard aluminum plate, generally used for mega yacht hulls, and a painted steel plate, generally used for ships, but the SLIPS did not reduce the drag as in the lab experiments.