New testing method for the evaluation of topographical gradients of varying strength

Passive gradient motion found in nature is becoming a point of interest for heat exchange and green energy technologies. Surfaces with topographical could potentially enhance exchanger performance, promote dropwise vs filmwise condensation, or delay icing on wind turbines by assisting the removal condensed impacted droplets. Coating-free surface tension gradients can be fabricated via various methods need to examined terms their capability spontaneous droplet motion. In this work, simple experimental method, coupled numerical modeling force analysis, examining variable-pitch micro/nanoengineered hierarchical superhydrophobic shown. The method was validated against calculations, allowing strength compared. most cases, model predictions travel distance velocity were within 20% measured data. This also useful design improvements absence horizontal surface.