Metamaterial Analysis Of Manipulating Mass Diffusion Process Based On Coordinate Transformation Theory

In recent years,metamaterials,which possess unique physical properties,have attracted the great interest of many researchers.This unprecedented composite materials have been expanded to other fields such as heat,acoustics and mechanics from optical cloak,new breakthroughs and achievements have als o born all the time.Being able to manipulate mass flow is critically important in a variety of physical processes in biomolecular science.However,the metamaterial for mass diffusion has been largely unexplored due to the largely difference between the d iffusion equation followed by the mass transfer and other wave equations.Therefore,the research finding on the mass diffusion law is much less.We present a practical case where a mixture of oxygen and nitrogen diffusing through a polymeric plannar matrix is separated.Given the theoretical basis of metamaterials is the theory of effective medium,and the principle behind mass metamaterial is the invariance of Fick's equations under coordinate transformation.Therefore,this article mainly rest on coordi nates transformation theory and effective media approach to achieve the purpose of mass diffusion management.To begin with,in order to realize the manipulation of the single component within the metamaterial region,two different homogeneous isotropic ma terials have been utilized alternately to achieve the function of artificial metamaterial.For the effect of cloaking nitrogen,the functional regime uses the alternating arrangement of concentric rings,filling two different types of isotropic materials,so the diffusivity of different rings for nitrogen varies.The selected materials with multilayer design eventually give rise to nitrogen cloak.There is an assume that the solubility of compounds oxygen and nitrogen is constant through the system.So,the accurate practical experiment have to take into account solubility in material.Secondly,we introduced a novel approach to rationally design mass-separator metamaterial devices that can cloak one molecular species while concentrate another.In order to realize the desired function of separating binary mixture of oxygen and nitrogen,based on the effective medium theory with "discrete-equivalent",four isotropic materials which conform to the requirements of the calculation result are selected,and then bi-function can be achieved simultaneously in a physical field.Last but not least,The concentration gradient at the core,the total mass flow towards the core,and the disturbance of the external concentration field are systematically examined in order to provide guidelines for the rational design and fabrication of metamaterial mass concentrator(cloak).Besides,in order to research various factors that affect mass diffusion process,the geometric structure characteristics of the physical model are analyz ed one by one.The results show that the internal radius R1,the number of concentric rings L,the solubility of species in the material and the discontinuity of gas concentration in the interface produce giant influence on the diffusion of gas.The theoretical research and analysis can selectively ignore the above factors,but in the actual experimental process,if these additional factors are not taken into account,the accuracy and results of the experiment will give rise to deviation.