Succulent leaves inspire liquid transport channels that can separate fluids

Thanks to its asymmetrically curved and tilted leaves, Crassula muscosa, a succulent commonly called the rattail crassula, has unique liquid transport properties and can guide liquids in a specific direction. Curious to see how these properties could be applied, Cui et al. studied C. muscosa’s mechanism of fluid transport and built synthetic channels that can separate combinations of fluids based on their surface tension.

“Think of the leaf surface as a series of tiny, tilted ratchets with curved shapes. Low-surface-tension liquids like alcohol spread easily and are pulled forward quickly. High-surface-tension liquids like water behave like droplets that don’t want to spread; they may move slowly or drip off,” said author Guoqiang Li. “Between these extremes, some liquids move bidirectionally or form a protruding film.”

After understanding how the leaves’ features effectively “read” surface tension — that is, their asymmetric curvature creating pressure differences in the fluids and their tilt guiding the flow — the group applied these properties to develop a passive, real-time surface tension sensor. They created artificial channels inspired by the leaves, incorporating LEDs that light up according to the fluid flow directions and heights, properties affected by the type of fluid combinations flowing through the channel.

By scaling down their C. muscosa-inspired sensors, adding temperature and pH sensitivity, and integrating them into more complex microfluidic networks, the researchers hope to enable several new applications.

“We are most excited about point-of-care diagnostics and microscale chemical separation — a cheap, disposable chip that automatically sorts liquids without external power,” Li said.

Source: “Multimodal liquid transport enabled by Crassula muscosa shoot inspired ratchet-shaped leaves channel,” by Zehang Cui, Liang Chen, Guoqiang Li, Dongxu Xiao, Haojie Xu, Yiyu Chen, Yaoxia Li, Haoyu Bai, Jiaxin Yu, and Moyuan Cao, Applied Physics Letters (2026). The article can be accessed at https://doi.org/10.1063/5.0334817 .