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Taking inspiration from ferns and hummingbirds to manufacture small-scale shape-morphing and liquid-capture devices - Emmanuel Siefert


Le 8 février 2024

Emmanuel Siefert

The fern sporangium uses capillary pressure at the scale of the cells to unbend the whole structure and release the spores. We will mimic this deformation mechanism by impregnating soft textured sheets that curl when the liquid evaporates. We will derive an analytical model to predict under which conditions such a curling occurs. I will additionally show that the shape of the deformed structure can be easily inverse programmed since its final curvature is directly related to the local textures’ geometry. 

Hummingbirds have developed a highly specialized tongue made of two soft open grooves that efficiently trap nectar by elastocapillary effects. Inspired by this observation, I will propose a fast and efficient fluid capture device at the capillary scale. The device consisting in many soft grooves stacked together on a flat sheet exhibits a sequential capillary rise when dipped in a liquid bath. Combining elasticity, capillarity, and viscous flow, we will show that the closure time of the sheet is controlled by the interplay between the geometric and physical parameters at play. Such structures may open the way for the design of optimal devices for fluid capture, aliquoting and transport in microfluidics.


Le 8 février 2024
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Complément lieu
LIPhy, salle de conférence

Publié le 7 février 2024

Mis à jour le 5 février 2024