Diffusion is known from immemorial times; laws for diffusion were elaborated by Adolf Eugen Fick.

Fick's laws of diffusion describe diffusion and can be used to solve for the diffusion, the concentration gradient (spatial derivative), or in simplistic terms the concept.

Alvin S. Fick has written:

'Across the fields' -- subject(s): Country life

Luise Fick has written:

'Die deutsche Jugendbewegung' -- subject(s): Youth movement

Once diffusion occurs it does not matter the MWCO of the membrane, but it depends on difference of concentration, as it is said in Fick's first law.