Neutral Polymer in Contact with an Electrolyte Solution

1 Neutral Polymer in Contact with an Electrolyte Solution 

We should consider the partitioning equilibria of the solvent molecules, the neutral salt and the ions formed by dissociation. For all mobile species, the equilibrium condition is 

The solvent (s) content in the polymer phase obviously depends on the difference between the standard chemical potentials (nf) of the solvent molecules in the two contacting phases, since 

Ions enter the film if their van der Waals and ion-dipole interactions with the polymer are large. Ions can be solvated (hydrated) by both the polymer and the solvent. A rough estimation can be achieved using Bom s theory. 

According to the Bom equation, the Gibbs free energy of solvation is 

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