Mass Separation by Metamaterials

Abstract

Being able to manipulate mass flow is critically important in a variety of physical processes in chemical and biomolecular science. For example, separation and catalytic systems, which requires precise control of mass diffusion, are crucial in the manufacturing of chemicals, crystal growth of semiconductors, waste recovery of biological solutes or chemicals, and production of artificial kidneys. Coordinate transformations and metamaterials are powerful methods to achieve precise manipulation of molecular diffusion. Here, we introduce a novel approach to obtain mass separation based on metamaterials that can sort chemical and biomolecular species by cloaking one compound while concentrating the other. A design strategy to realize such metamaterial using homogeneous isotropic materials is proposed. We present a practical case where a mixture of oxygen and nitrogen is manipulated using a metamaterial that cloaks nitrogen and concentrates oxygen. This work lays the foundation for molecular mass separation in biophysical and chemical systems through metamaterial devices.

Optimization-based design of an elastostatic cloaking device

“…Beyond electromagnetism, transformation optics was used for the design of metamaterials for heat conduction 4 , 5 , mass diffusion 6 , 7 , and acoustics 8 – 10 .…”

Anisotropic membrane materials for gas separations

“…Recent progress in mass diffusion metamaterials, however, has begun to create unprecedented ways to manipulate the direction of mass flux. [23][24][25][26][27][28] A membrane that manipulates mass flux direction can control the trajectory of the compounds of interest and create spatial areas where the flux of the desired molecule is focused, or alternatively spatial areas where undesirable molecules are prevented from penetrating. Importantly, the rerouting of molecules to different locations provides a new physical principle that can be exploited to design gas separations.…”

“…Such directional control of mass flux can be achieved in practice by means of engineered anisotropic membrane materials. 23,28 In practice, fabrication of these anisotropic membrane materials involves the use of layered arrangements of isotropic materials. Despite their unique potential, the design, operation, capabilities, and limitations of anisotropic membrane materials to achieve gas separations are still largely unexplored.…”

“…In these materials, mass transfer occurs isotropically meaning that it is difficult to guide mass flow paths in controlled ways. Recent progress in mass diffusion metamaterials, however, has begun to create unprecedented ways to manipulate the direction of mass flux . A membrane that manipulates mass flux direction can control the trajectory of the compounds of interest and create spatial areas where the flux of the desired molecule is focused, or alternatively spatial areas where undesirable molecules are prevented from penetrating.…”

“…Importantly, the rerouting of molecules to different locations provides a new physical principle that can be exploited to design gas separations. Such directional control of mass flux can be achieved in practice by means of engineered anisotropic membrane materials . In practice, fabrication of these anisotropic membrane materials involves the use of layered arrangements of isotropic materials.…”