A Novel Sprayable Slippery Poylmer Coating for Drag Reduction

Reducing hydrodynamic friction drag on marine vehicles can lead to significant environmental and economic benefits. Lubricant-infused surfaces (LIS) and superhydrophobic surfaces (SHS) have received significant attention as promising candidates for achieving this goal. However, these conventional low-friction surfaces tend to lose their effectiveness when exposed to external forces, including flow-induced shear forces. This is because when LIS and SHS are subjected to high-speed flows, they can lose their entrapped lubricant and air plastron, respectively. Improving the robustness of entrapped fluids against external shearing flows is essential to achieve sustainable drag reduction in real turbulent environments.

In this study, we fabricated a scalable slippery low-friction surface containing lubricant-infused micro-spherical cavities using the spraying breath figure method. The unique surface topography effectively retains the infused lubricant even under harsh flow conditions. As a result, the new scalable slippery surface achieved a significant drag reduction rate in turbulent flow conditions, similar to those experienced by typical container ships cruising on the ocean.