


A surface with 3D ratchet structures, which enable liquids of different surface tensions to spread in different directions, inspired by Araucaria leaves
City University of Hong Kong
A strange leaf has inspired a new type of material that can affect the flow of liquids. The scaly texture of the leaf forces fluids with different properties to flow in opposite directions – even if one of those directions is uphill.
Araucaria is a genus of evergreen trees – including some known as monkey puzzles – with spiky, cylindrical leaves made up of smaller, scale-like segments called ratchets. Zuankai Wang …

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