Stephan Rudykh (Soft Matter Laboratory, University of Wisconsin, Madison, USA). Instabilities for Dynamically Tunable Patterns and Functions of Soft Materials.

Nature actively uses sophisticated designs of microstructures to achieve astonishing material properties and functionalities. Thus, microstructures give rise to the incredible toughness of mother-of-pearl. Another example is an octopus, an amazingly effective soft machine created by the nature. The creature can squeeze its whole body through an extremely narrow space while preserving a large variety of functionalities. The nature created soft machine comprises highly deformable composites that are characterized by different dynamically tunable microstructures and phase properties, depending on the required functionalities. Indeed, such materials are highly desirable for many applications including human-interactive soft robotics, and novel actuators and sensors, and biomedical devices.

In this presentation, I will specifically focus on the role of microstructures in the performance of deformable multifunctional composites. We will consider how large deformations and elastic instabilities can be used to trigger dramatic pattern transformations, and to control a large variety of functionalities; in particular, the design of switchable acoustic metamaterials will be discussed. The recently discovered new type of instability-induced domain formations in soft composites will be presented.

Analytical and numerical findings, as well as experimental results of 3D-printed soft composites will illustrate the ideas.