The layer may either be Insulating,
Resistive (supporting electrolytes only), or an
Ion exchange membrane.
For Resistive or
Ion exchange membrane, the potential drop over the membrane is determined either from the
Surface resistivity or the
Thickness and conductivity.
For Ion exchange membrane, the choice of
Charge-carrying species concentration species specifies that the current flowing over the layer will be carried by this species (which must have a nonzero charge number). The potential condition may be either
Donnan,
which will calculate the potential shift over the boundary based on the membrane charge carrying species concentration, or
User defined.