A Metafluid With Multistable Density and Internal Energy States

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. In this work, we suggest to achieve this goal by following the approach used in meta-materials and suggest to control the macro-properties of a fluid by selecting a micro-structure composition. Specifically, we study analytically and experimentally a suspension composed of gas, enclosed within multi-stable elastic capsules, and lubricated by second external fluid. By coupling multi-stability of the capsules and the associated hysteresis, a fluid with multiple stable density points for a given pressure and temperature states can be created. Such suspensions allow to harvest, store, and release energy due to specific external variations in pressure or temperature. With today’s technology, it is possible to “program” the properties of the multi-stable particles and combine them with carefully selected properties of the gas and liquid components of the suspension. Thus, this work paves the way for creating new fluids that feature optimal behavior, high efficiency and safety for energy and refrigeration cycles.