In This Issue

Like the leaves of the lotus plant, highly water-repellent surfaces known as superhydrophobic surfaces exhibit a remarkable ability to remove contaminating particles. Researchers commonly attribute the self-cleaning property, dubbed the lotus effect, to the action of water droplets rolling across the superhydrophobic surface under the influence of gravity. Katrina Wisdom et al. (pp. 7992–7997) report that water vapor can condense onto a superhydrophobic surface and produce self-propelled droplets of liquid condensate, which encloses contaminating particles and removes them via a jumping motion. Using the cicada wing as a model, the authors demonstrate that surface energy, released when a liquid condensate coalesces around a foreign particle, drives this jumping motion with sufficient force to dislodge particles similar in size to plant pollen and soil dust. Furthermore, the authors show that the process can spontaneously clean contaminants from superhydrophobic cicada wings that cannot be removed by gravity, wing vibration, or wind. The findings reveal a previously unreported mechanism for removing contaminants from superhydrophobic surfaces that may aid the development of self-cleaning materials, according to the authors. — T.J. IN T H IS I S S U E