Chapman McDaniel and Venmathy Rajarathinam

Diffusivity: Gases, Liquids, and Solids

This picture is an example of  liquid-liquid diffusion.  As time progresses, the solute spreads throughout the solvent causing it to have a bluish tint.

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Diffusion is the process by which a substance intermingles through a homogeneous solution (gas, liquid or solid) due to a difference either in concentration or chemical potential.  The diffusion coefficient also called the diffusivity is the proportionality constant between the rate of diffusion and the gradient of the potential causing diffusion.  This website will present some basic theory on diffusion, modeling equations for diffusivity, and a Matlab Code that will calculate diffusivities for gases, liquids, and solids.