RESCHEDULED Robin Selinger (Kent State)
Date: Thu. March 19th, 2020, 4:00 pm-5:00 pmLocation: Rockefeller 301
New date to be determined
Modeling liquid crystal elastomers: from auto-origami to responsive surfaces and a light-powered soft robot
Liquid crystal elastomers combine the orientational order of liquid crystals with the elasticity of polymers. Remarkably, these materials flex and deform reversibly, driven by stimuli such as illumination or heating, and can be programmed to morph from simple to complex shapes. The material’s liquid crystal director field, indicating the direction of molecular alignment, defines the local axis of induced contraction. We use GPU-based finite element elastodynamics modeling to study how patterns with director gradients and topological defects give rise to complex actuation. Resulting structures include twisting and undulating ribbons, self-folding boxes, and deformable surface coatings with spikes, indentations, and microchannels. To design a responsive surface that mimics the shape of octopus suckers, we modify the core structure of topological defects to induce regions of positive and negative Gaussian curvature. We also model the generation of continuous light-driven mechanical wave motion in a photoactive liquid crystal polymer film that our experimental collaborators used to create a light-powered soft robot [1]. Work supported by NSF-DMR 1409658, NSF-CMMI 1436565, and NSF-CMMI 1663041. [1] Anne Helene Gelebart, Dirk Jan Mulder, Michael Varga, Andrew Konya, GhislaineVantomme, E. W. Meijer, Robin L. B. Selinger*, and Dirk J. Broer*, “Making waves in a photoactive polymer film,” Nature v. 546, p. 632, 29 June, 2017.