S1E6
Episode 6 (August 16, 2020)
Binbin Ying
McGill University and University of Toronto
Yunfang Yang
University of Oxford
Guoyong Mao
Johannes Kepler University Linz
An ambient-stable and stretchable ionic skin with multimodal sensation
Abstract:
Skin serves as a physical and hygroscopic barrier to protect the inner body, and also contains sensory receptors to perceive environmental and mechanical stimuli. To recapitulate these salient features, hydrogel-based artificial skins have been developed. However, existing designs are constrained by limited functionality, low stability, and requirement of external power. Herein, a novel artificial ionic skin (AIskin) – an analog of the diode based on controlled ion mobility – is demonstrated with high toughness, stretchability, ambient stability and transparency. The AIskin consists of a bilayer of oppositely-charged, double-network hydrogel, and converts mechanical stimuli and humidity into signals of resistance, capacitance, open-circuit voltage (OCV), and short-circuit current (SCC), among which the OCV- and SCC-based sensing signals are self-generated. Its multimodal sensation is maintained in a wide range of relative humidities (13–85%). It is demonstrated for wearable strain-humidity sensing, human–machine interaction and walking energy harvesting. This work will open new avenues toward next-generation, skin-inspired wearable electronics.
Modular Origami-inspired Kinematic Metamaterial
Abstract:
Mechanical metamaterials are artificial materials with tailored structural cells that exploits motion, deformation and shape morphing. These materials can transform into different shapes in response to mechanical stimuli, leading to superior properties such as tunable stiffness, reconfigurable topology and advantage in energy absorption. In recent years, origami and kirigami provide many inspirations in the geometry structure of the metamaterials. This talk will start from an introduction to the Deployable Structure Group at Oxford, and explain analytical approaches to study origami through kinematic models of linkage mechanisms. Then, a series of origami/kirigami inspired kinematic-induced metamaterials will be presented. The reconfigurability of the origami structures provides the material with a continuously changing shape, which can be used in electromagnetic, photonic and acoustic fields for tunable metamaterials. Some applications of the proposed metamaterial will be included, and discussion on future work will be given in the end.
Soft electromagnetic robots
Abstract:
Rigid electromagnetic actuators serve our society in a myriad of ways for more than two hundred years. Yet, their bulky nature restricts close collaboration with humans. Here we introduce soft electromagnetic actuators (SEMAs) by replacing solid metal coils with liquid metal channels embedded in elastomeric shells. We demonstrate human-friendly, simple, stretchable, fast, durable, and programmable centimeter-scale SEMAs that drive a soft shark, interact with everyday objects, or rapidly mix a dye with water. A multi-coil flower SEMA with individually controlled petals blooms or closes within tens of milliseconds and a cubic SEMA performs programmed, arbitrary motion sequences. We develop a numerical model supporting design and opening potential routes toward miniaturization, reduction of power consumption and increase of mechanical efficiency. SEMAs are electrically controlled shape morphing systems that are potentially empowering future applications from soft grippers to minimally invasive medicine.