Separation and characterization of polymers applying full adsorption/desorption approaches

The present contribution is a review of the recent progress in combining a full adsorption/desorption procedure with size exclusion chromatography (FAD/SEC) for the separation and characterization of (co)polymers. FAD includes complete and selective adsorption of the polymer sample to be separated from an adsorption promoting-liquid (adsorli) onto an appropriate adsorbent, which is packed in an especially designed LC-like (micro) column. In the following steps, macromolecules are successively displaced from the adsorbent by different eluents with increasing desorbing strength. Adsorption and desorption of macromolecules are generally governed by their molecular characteristics, primarily by their molar mass (MM) and their chemical nature, that is, by their chemical composition (CC). Therefore, fractionation of polymers according to these parameters can be reached in the course of the FAD process. In this respect, a coupling of an SEC instrument with the FAD column has turned out to be very advantageous. The on-line SEC enables monitoring the amount, molar mass and molar mass distribution of macromolecules leaving the FAD column. In this way, constituents of polymer blends can be discriminated and independently characterized. Advantages and problems associated with the applications of FAD approaches are outlined. The assessment of dynamic adsorption/desorption of macromolecules onto/from solid surfaces as part of the optimization procedure is discussed as well.