Crassula muscosa. Photo ©2006 Derek Ramsey. Location credit to the Chanticleer Garden. CC BY-SA 3.0

Going with the flow of nature

3 July 2024

Researchers at Hong Kong Polytechnic University have made a significant discovery in the field of fluid dynamics, revealing how the succulent plant Crassula muscosa, native to Namibia and South Africa, can selectively control the direction of liquid flow. This study, led by Professor Wang Liqiu from the Department of Mechanical Engineering, has potential applications in various technologies, including microassays (laboratory tests that use very small amounts of samples and reagents to measure biological or chemical activity), medical diagnostics, and solar desalination.

Published in the journal Science, the study demonstrates that Crassula muscosa will transport liquids in opposite directions depending on the conditions. When two shoots of the plant were infused with the same liquid, one directed the flow towards the tip while the other channelled it towards the root. This unique ability to control liquid direction could inspire new developments in nature-inspired materials and fluid dynamics technologies.

The research, carried out in collaboration with the University of Hong Kong and Shandong University, highlights the plant's adaptation to its arid but foggy environment, where efficient water management is crucial for survival.

If scientists can mimic this natural mechanism, they will be able to improve human-made systems that require precise liquid control. This would open new avenues for developing technologies that rely on directional liquid transport, such as water harvesting and heat transfer systems. The findings underscore the potential for finding innovative solutions for engineering and material science in the natural world.