Investigating and tailoring the thermodynamic properties of different fluids is crucial to many fields. For example, the efficiency, operation range, and environmental safety of applications in energy and refrigeration cycles are highly affected by the properties of the respective available fluids. Here, we suggest combining gas, liquid and multistable elastic capsules to create an artificial fluid with a multitude of stable states. We study, theoretically and experimentally, the suspension’s internal energy, equilibrium pressure-density relations, and their stability for both adiabatic and isothermal processes. We show that the elastic multistability of the capsules endows the fluid with multistable thermodynamic properties, including the ability of capturing and storing energy at standard atmospheric conditions, not found in naturally available fluids.

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Growing soft materials which follow a three dimensional (3D) path in space are critical to applications such as search and rescue and minimally invasive surgery. Herein, a concept for a single‐input growing multi‐stable soft material, based on a constrained straw‐like structure is presented. This class of materials are capable of maneuvering and transforming their configuration by elongation while executing multiple turns. This is achieved by sequenced actuation of bi‐stable frusta with predefined constraints. Internal viscous flow and variations in the stability threshold of the individual cells enable sequencing and control of the robot's movement so as to follow a desired 3D path as the structure grows. A theoretical description of the shape and dynamics resulting from a particular set of constraints is derived. To validate the model and demonstrate the suggested concept, experiments of maneuvering in models of residential and biological environments are presented. In addition to performing complex 3D maneuvers, the tubular structure of these robots may also be used as a conduit to reach inaccessible regions, which is demonstrated experimentally.

The thermodynamic properties of fluids play a crucial role in many engineering applications, particularly in the context of energy. Fluids with multistable thermodynamic properties may offer new paths for harvesting and storing energy via transitions between equilibria states. Such artificial multistable fluids can be created using the approach employed in metamaterials, which controls macro‐properties through micro‐structure composition. In this work, the dynamics of such “metafluids” is examined for a configuration of calorically‐perfect compressible gas contained within multistable elastic capsules flowing in a fluid‐filled tube. The velocity‐, pressure‐, and temperature‐fields of multistable compressible metafluids is studied by both analytically and experimentally, focusing on transitions between different equilibria. The dynamics of a single capsule is first examine, which may move or change equilibrium state, due to fluidic forces. The interaction and motion of multiple capsules within a fluid‐filled tube is then studied. It shows that such a system can be used to harvest energy from external temperature variations in either time or space. Thus, fluidic multistability allows specific quanta of energy to be captured and stored indefinitely as well as transported as a fluid, via tubes, at standard atmospheric conditions without the need for thermal isolation.