S1E12
Episode 12 (September 27, 2020)
Florian Hartmann
Johannes Kepler University Linz
Huichan Zhao
Tsinghua University
Bolei Deng
Harvard University
A resilient biogel for soft robotics and electronics
Abstract:
Biodegradable and biocompatible elastic materials for soft robotics, tissue engineering or stretchable electronics with good mechanical properties, tunability, modifiability or healing properties drive technological advance, and yet they are not durable under ambient conditions and do not combine all the attributes in a single platform. We have developed a versatile gelatin-based biogel, which is highly resilient with outstanding elastic characteristics, yet degrades fully when disposed. It self-adheres, is rapidly healable and derived entirely from natural and food-safe constituents. We merge all the favourable attributes in one material that is easy to reproduce and scalable, and has a low-cost production under ambient conditions. This biogel is a step towards durable, life-like soft robotic and electronic systems that are sustainable and closely mimic their natural antetypes.
Actuation, Sensation, and Control of Soft Robots
Abstract:
Due to their continuous and natural motion, soft robots have shown potential in a range of robotic applications including bio-inspired robots, wearable devices, and industry. Despite these advantages and the rapid developments in recent years, robots using soft actuators still have several challenging issues to be addressed. In this talk, I'll present some of our recent work in the area of soft robotics, covering the topics of actuation, sensation and control of soft robots.
Programmed topological transformations of cellular microstructures through liquid-induced transient softening and assembly
Abstract:
The fundamental topology of cellular structures―the location, number, and connectivity of nodes and compartments―can profoundly impact their acoustic, electrical, chemical, mechanical, and optical properties, as well as heat, fluid and particle transport. Approaches harnessing swelling, electromagnetic actuation as well as mechanical instabilities in cellular materials have enabled a variety of interesting wall deformations and compartment shape alterations, but the resulting structures generally preserve the defining connectivity features of the initial topology, as overcoming the particularly high elastic resistance for repacking at each node presents a unique challenge. Here we introduce a two-tiered dynamic strategy to achieve systematic reversible transformations of the fundamental topology of cellular microstructures that can be applied to a wide range of material compositions and geometries. Our approach only requires exposing the structure to a liquid whose composition is selected to have the ability to first infiltrate and soften the material at the molecular scale, and then, upon evaporation, to form a network of localized capillary forces at the architectural scale that zip the edges of the softened lattice into a new topological structure, which subsequently re-stiffens and remains kinetically trapped. Reversibility is induced by applying a mixture of liquids that offer modular temporal control over the sequence and extent of the softening-evaporation-stiffening actions, restoring the original lattice or providing access to a repertoire of intermediate reconfiguration modes. Guided by a generalized theoretical model connecting cellular geometries, material stiffness and capillary forces, we first demonstrate programmed reversible topological transformations of triangular lattices into hexagonal ones, and then expand this strategy to a variety of complex closed-cell geometries. We then harness dynamic topologies for developing active surfaces with information encryption, selective particle trapping, and tunable mechanical, chemical and acoustic properties, as well as multi-stimuli actuation.