Livings in nature have unique surface morphology and/or chemistry to perform special function, including wetting properties. For instance, peristome of Nepenthes alata has sharp edges facing the same direction, which help to transport liquid in one direction by both capillary rise effect and pinning effect. This nature functions offered excellent applications as anti-wetting or fluidic materials in various fields. Thus, discovery of novel wetting properties in nature is quite crucial to open opportunities to develop novel functional materials. Here, we discover nature phenomenon that Lampropeltis pyromelana (Arizona Mountain Kingsnake) performs unidirectional water spreading property on the ventral scales. When a water droplet is settled on the scales and the volume of water is increased, the droplet was pinned at a scale edge but spread in the direction of snake head (see Figure). The unique wetting property is owing to anisotropically aligned sharp structures on the snake scales. The edges prevent backflow of water by pinning force and help water spreading in the head direction by capillary rise effect. Furthermore, bioinspired by the morphology of L. pyromelana, we design a unidirectional wetting surface using 3D printing process. We expect that the unidirectional wetting property can contribute to develop fluidic systems such as self-lubrication and non-powered liquid delivery.

Unidirectional wetting phenomenon on the snake scales

255th National Meeting (2018)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.