Enhancing Droplet Deposition on Wired and Curved Superhydrophobic Leaves.

Droplet deposition on superhydrophobic surfaces has been a great challenge owing to the shortness of the impact contact time. Despite recent research progress regarding flat superhydrophobic surfaces, improving deposition on ubiquitous wired and curved superhydrophobic leaves remains challenging as their surface structures promote asymmetric impacts, thereby shortening the contact times and increasing the likelihood of droplet splitting. Here, we propose a strategy to solve the deposition problems based on an analysis of the impact dynamics and a rational selection of additives. Combining the prominent extension property of flexible polymers with surface tension reduction of the surfactant, the well-chosen binary additives cooperatively solve retention and coverage problems by limiting the fragment and enhancing local pinning and wetting processes at a very low usage. This work advances the understanding of droplet deposition by rationally selecting additives based on the impact dynamics, which is believed to be useful in a variety of spraying, coating, and printing applications.