Gibbs-Donnan effect

The Gibbs-Donnan effect (also known as the Donnan effect, Donnan law, Donnan equilibrium, or Gibbs-Donnan equilibrium) is a name for the behavior of charged particles near a semi-permeable membrane to sometimes fail to distribute evenly across the two sides of the membrane.^[1] The usual cause is the presence of a different charged substance that is unable to pass through the membrane and thus creates an uneven Donnan potential.