EuglenaShells: morphable, modular and reusable metasurfaces inspired by the active envelope of Euglena cells

Surface morphing is difficult because of Gauss’ Egregium Theorem, by which changes in Gaussian curvature require in-plane stretching/shearing [1]. This theorem is also at the root of geometric rigidity of curved shells. Thus, a surface with adaptable in-plane deformability may switch between rigidity and malleability. Here, we develop a novel concept for Gaussian morphing, EuglenaShells, inspired by Euglena cells. EuglenaShells are metasurfaces made of parallel slidable strips, which morph by sliding patterns between strips [2,3]. In existing morphable metasurfaces, sub-units (strut-joint lattices, swelling/pneumatic domains, origami/kirigami motifs) eventually lock, limiting the extent of morphing. Specific transformations require custom designs, hindering reusability and control of mechanics. EuglenaShells largely overcome these limitations. Sliding being unlimited, EuglenaShells show extreme morphing compatible with small strains in the slender sub-units. They are modular, reusable, and have tuneable mechanical properties (fluid, plastic, elastic, rigid) depending on the sliding interactions. These features of EuglenaShells will be illustrated with computer simulations and physical realizations at different scales.



[1] Klein, Efrati, Sharon, Science 315, 1116–1120 (2007).

[2] Arroyo, DeSimone, J. Mech Phys Solids 62, 99–112 (2014).

[3] Noselli, Beran, Arroyo, DeSimone, Nature Physics 15, 496-502 (2019).