Nonlinear Physics Seminar: "New prospects in non-Euclidean sheets: unexplored shaping pathways 4D printing and autonomous actuation "

Wed, 16/06/202112:00-13:30
Danciger B Building, Seminar room
Lecturer: Ido Levin, The Hebrew University of Jerusalem, Israel
Living organisms have mastered the dynamic control of stresses within sheets to induce shape transformation and locomotion. For instance the spatiotemporal pattern of action-potential in a heart yields a dynamical stress field leading to shape changes and biological function. Such structures inspired the development of theoretical tools and responsive materials alike. Yet present attempts to mimic their rich dynamics and phenomenology in autonomous synthetic matter are still very limited. In this talk I will present my PhD research focused on several complementing achievements towards this goal. First I will introduce a novel shaping mechanism that was overlooked by previous research. This mechanism results in atypical geometrical frustration and scaling laws for the shape transition. Next I will present a new fabrication technique of programmable structures via 4D printing of pixelated gel structures. This strategy provides arbitrary control over the geometry of the printed material. Finally in the main part of my talk I will present the first autonomous shape-morphing membranes: thin sheets of responsive gel that shrink and swell in response to the phase of an oscillatory chemical reaction. Propagating reaction fronts induce localized deformation of the gel. I demonstrate how these localized deformations prescribe dynamic patterns of curvature leading to time-periodic global shape changes. Together these innovations present a route for modelling and developing fully autonomous soft membranes mimicking some of the locomotive capabilities of living organisms.