A method of determining the diffusion coefficient
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It is proposed to determine the diffusion coefficient by the moving boundary method, without using a solution of the diffusion equation, by studying the finishing stage of boundary movement in appropriate coordinates, which take account of the symmetry and characteristic dimensions of the system.
The method is suitable for systems with the symmetry of a plate, a round cylinder, or a sphere, at an arbitrary dependence of the diffusion coefficient on concentration of the diffusing substance.
In the case of spinning solutions, the studies may be carried out by observing the movement of the optical boundary in a round drop which is flattened out in the gap between two transparent plates, where, at a certain moment of time, a liquid containing the diffusing substance is introduced.
KeywordsPolymer Diffusion Coefficient Diffusion Equation Characteristic Dimension Boundary Movement
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