Diffusion polarization at lipid bilayer membranes

Summary Expressions are derived for the decrease of the conductivity of lipid bilayer membranes caused by diffusion polarization in the aqueous solutions near the membrane. It is assumed that after a sudden change in the voltage or current, the reestablishment of the stationary state within the membrane is fast as compared to the change of ion concentration in the solutions. The time course of the diffusion polarization, then, can be calculated for experiments where either the voltage or the current are controlled. Criteria are given to distinguish diffusion polarization from other relaxation processes, and several limiting cases of experimental interest are discussed.