Existence and role of large micropillars on the leaf surfaces of The President lotus.

It is reported that a lotus surface has hybrid micro/nanostructures (i.e., small micropillars are covered with nanopillars), which make a water drop easily roll off from the lotus surface. However, we have recently found that, in addition to nanopillars and small micropillars, there also exist sparsely distributed large micropillars on the leaf surface of The President lotus. Accordingly, in this work, we examined the effects of these large micropillars on the wetting properties of The President through four types of wetting experiments: pressing tests, measurement of tilt and contact angles, condensation, and evaporation. For the purpose of comparison, we also did the same experiments on the leaf surfaces of another two lotuses, Carolina Queen and Chawan Basu, which only have hybrid micro/nanostructures. The President, Carolina Queen, and Chawan Basu are three different lotus varieties.