Solvatation préférentielle des polymères: Effet de la masse moléculaire sur les résultats expérimentaux et comparaison avec les prévisions théoriques

The preferential solvation coefficient λ′ has been studied as a function of the molecular weight of the polymers and the composition of the mixed solvents for the following ternary systems: polystyrene/benzene/cyclohexane, poly(2‐vinylpyridine)/benzene/cyclohexane, polystyrene/benzene/methanol, polystyrene/carbon tetrachloride/methanol and poly(2‐vinylpyridine)/chloroform/ethanol. It is shown that the extrapolated value λ′∞ for infinite molecular weight better obeys the theoretical expressions established by Read and Pouchly than the value for a finite molecular weight. When interactions are weak the Read formula can be used, when they are stronger one has to use the formula on Pouchly et al., but all these theories give just a qualitative description of the phenomenon and cannot be used quantitatively in the presence of strong interactions such as hydrogen bonds.