PARTITIONING INVERSION OF A BIMODAL POLYMER-SOLUTION IN CONFINED GEOMETRIES

The partitioning of solvated polymer molecules with a bimodal molecula r weight distribution between a confined geometry such as a porous med ium and an external free volume has been investigated. Applying the re sults of renormalization group theory, we derive the chemical potentia ls in the interior and exterior of the pore for each fraction of the p olymer in equilibrium. It was found that, as the concentration of the high molar mass macromolecule exceeds the overlap concentration in the exterior, the low molar mass fraction is driven into the restricted p ore channels, while the high molar mass fraction remains outside. We n ote that this segregation effect could in principle be used to recover a low molar mass fraction in high purity from a mixture. The implicat ion of this finding with respect to size-exclusion chromatography is a lso briefly mentioned.