Attractive electric forces, summary

With this in mind, the impossibility of forming a double layer by electric forces only is obvious. Any ion that may attach to a particle will create a potential that keeps out all other ions of the same sign. Accumulation of a number of identical charges on a surface can take place only if the adsorbing ions experience a non-electric affinity for the surface so that they can move against the adverse potential. The extent to which this occurs depends on the balance between the attractive non-electrostatlc and the repulsive electric forces. In summary the reason for the formation of relaxed double layers is the nonelectric afflnlty of charge-determining ions for a surface the extent to which the double layer develops is determined by the non-electrostatlc electrostatic interaction balance. 

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