Geometric effects on retention capacity in liquid-infused surfaces

The shear-driven drainage of liquid-infused surfaces can be modified by longitudinal variation in the surface's underlying geometry. Because liquid-infused surfaces are playing an increasingly important role in a new generation of drag-reducing and omniphobic materials, the ability to manipulate and optimize their fluid retention capacity is crucial to improving material robustness. Theoretical and numerical calculations are performed on the steady-state fluid retention in streamwise-varying, open-capillary channels, with emphasis on the effect of interfacial deformation on resisting fluid drainage. Optimal substrate geometries and corresponding manufacturing tolerances for the production of efficient surfaces are developed as a function of the parameters accounting for interface deformation and channel geometry.