Rain drops, norming dew, fog, spray paint, injected fuel in engines, aerosol inhalation treatment, range hood in kitchen, vape (aka e-cigarette), arc welding etc. You can find droplets of liquid (water, oil, and metal) everywhere. Droplets are small and fascinating, especially when they appear in nature. Please see some of our related studies below.
S. caninervis is one of the most common desert mosses in the world, widely distributed across the drylands from the Mojave Desert in the United States, parts of Europe, to the Gurbantuggut Desert in China. S. caninervis has a unique adaptation to survive: it uses a tiny hair on the end of each leaf to collect water, in addition to that collected by the leaves themselves.
We found that the unique multiscale structures of the hair are equipped to collect and transport water in four modes: i) nucleation of water droplets and films on the leaf hair from humid atmospheres; ii) collection of fog droplets on leaf hairs; iii) collection of splash water from raindrops; and iv) transportation of the acquired water to the leaf itself. This project was featured on the cover of Nature Plants, was one of the most read articles in journalin a three-year period, and was highlighted in Nature, Science, the Washington Post, etc. This moss not only shows the awesomeness of mother nature, but also inspires us to design many water harvest and conservation devices.
Inspired by the huge droplets attached on cypress tree leaf tips in the Temple of the Earth, Beijing after a heavy rain, we find that a bent fibre can hold significantly more water in the corner than a horizontally placed fibre.
The maximum volume of the liquid that can be trapped is remarkably affected by the bending angle of the fibre and Bond number of the liquid. We experimentally and theoretically find the optimal included angle (∼36°) that holds the most water.
This fundamental research was featured on the back cover of Soft Matter, and has inspired novel hydroponic techniques that use much less water.