This is a very complex multi-nanometer and micro-scale ultrastructure. The average size of papillae on the surface of lotus leaf is about 10 micron, and each papillae consists of many protrusions with a diameter of about 200 nm. When it comes into contact with rain, it will make the rain form a ball and absorb the dust on the lotus leaf.
If we carefully observe the surface of the lotus leaf, it is not as smooth and seamless as we can see with the naked eye, but there are many protruding substances on it. The concave parts of these mastoid structures are filled with air, which can form an air layer with nanometer thickness on the lotus leaf, so it is also an extremely thin air film on the leaf. The lotus leaf can secrete some plant wax, so when dust and rain fall on the lotus leaf, it can form a special "lotus leaf".