Introduction to Multidimensional Polymer-LC

The possibility to create a huge variety of different polymeric structures allows tailoring the properties of macromolecular materials for specific applications. A common feature of all polymers is heterogeneity, arising from the statistical processes involved in all polymerization reactions. Even linear homopolymers contain chains of different molar mass, giving rise to the well-known molar mass distribution (MMD). The introduction of additional comonomers adds another level of complexity, as the distribution of the comonomers over the different chains gives rise to a chemical composition distribution (CCD). Other heterogeneities may arise from differences in end-group functionalization, branching, microstructure etc.

Typically, macromolecules are separated by their size in solution using Size Exclusion Chromatography (SEC, GPC). However, chains of different chemical composition or topology might have similar sizes, resulting in coelution of two non-identical structures at the same elution volume. The same applies to separations based on a “generic” adsorption strength, as a small molecule composed of strongly adsorbing repeating units might experience the retention than a large molecule composed of weakly adsorbing repeating units.

As a consequence, one dimensional separating techniques are in most cases insufficient to provide information on the full heterogeneity of modern complex polymers.

2-dimensional chromatography combines separations based on different structural features, providing a wealth of information on the heterogeneity of complex polymers.

The presentation will introduce the concept of 2-dimensional chromatography, the instrumental setup as well as typical applications.

Presenter: Wolfgang Radke (Head of PSS R&D, PSS)

Wolfgang Radke studied polymer chemistry in Mainz (Germany) and Amherst (MA, USA). In his positions at the German Plastics Institute (DKI), the Fraunhofer Institute for Structural Durability and System Reliability LBF, and at PSS Polymer Standards Service GmbH, he specialized in liquid chromatography of polymers, particularly in interaction and two-dimensional chromatography.