Condensation and jumping relay of droplets on lotus leaf

TL;DR

This study investigates the dynamic behavior of condensed water droplets on lotus leaf surfaces, revealing a jumping relay phenomenon that enhances self-cleaning by autonomous droplet removal.

Contribution

It introduces the observation of out-of-plane jumping relay of droplets on lotus leaves and analyzes the energy dissipation mechanisms controlling droplet rebounding.

Findings

Droplets can jump relay triggered by falling droplets.

Jumping relays maintain high speed over multiple events.

Surface tension energy dissipation influences droplet rebound size and velocity.

Abstract

Dynamic behavior of micro water droplet condensed on a lotus leaf with two-tier roughness is studied. Under laboratory environment, the contact angle of the micro droplet on single micro papilla increases smoothly from 80 deg to 160 deg during the growth of condensed water. The best-known "self-clean" phenomenon, will be lost. A striking observation is the out-of-plane jumping relay of condensed droplets triggered by falling droplets, as well as its sustained speed obtained in continuous jumping relays, enhance the automatic removal of dropwise condensation without the help from any external force. The surface tension energy dissipation is the main reason controlling the critical size of jumping droplet and its onset velocity of rebounding.