Drag reduction based on vapor stabilized surfaces on underwater superhydrophobic surfaces.

Superhydrophobic surfaces have proven to be beneficial for marine and submarine vehicles as they effectively reduce drag. This drag reduction is achieved through the creation of a thin layer of air known as the "plastron," which forms within the asperities of the textured surface between the solid material and the surrounding liquid. However, this plastron layer is inherently unstable due to factors such as hydrostatic pressure, air diffusion in water, and the instability caused by the shearing flow over the surface.

Efforts were made to create vapor-stable surfaces that could effectively tackle the challenge of plastron instability and for drag reduction. This was achieved by modifying the surface morphologies using micro, nano, hierarchical, and re-entrant geometries. Using a low-cost and scalable fabrication method, superhydrophobic surfaces based on nanofillers with highly re-entrant geometry was manufactured. The outcome resulted in significant drag reduction, primarily attributed to the improved stability of the vapor within the surface textures.

In summary, vapor-stable surfaces through advanced surface morphologies, have successfully increased the stability of the plastron layer providing a significant reduction in drag.