Enthalpy polymer/salt dissolution

Both entropy and enthalpy change have to be considered when dissolving a salt in any solvent Dissolution can lead to either a positive or negative overall entropy change. In polymer electrolytes, a negative entropy of dissolution is common and can be an important consideration at higher temperatures. This effect arises because the dielectric constant of the solvent polymer (solid or liquid) is usually... 

In the simplest analysis, an entropy increase favours dissolution, due to the dissociation of the crystal into the maximum number of independent particles. The main differences in solubility in various solvent/salt combinations reflect differences in the lattice enthalpy of the salt, cohesive enthalpy of the solvent and the solvation enthalpy. Conditions which favour dissolution are (i) a low lattice energy of the salt (ii) a low cohesive energy of the polymer and (hi) a high solvation energy. 

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