Liquid chromatography of theta-shaped and three-armed star poly(tetrahydrofuran)s: theory and experimental evidence of topological separation.

A theoretical background is provided for the methods of the analysis and topological separation of complex macrocyclic polymers by means of size exclusion chromatography (SEC), liquid adsorption chromatography, and liquid chromatography at the critical condition. We focus on a particular problem of the separation of theta-shaped polymers from its three-armed star analogues. Based on the theory, we simulate chromatograms for model mixtures of polydisperse theta- and star-polymers and analyze conditions for good separation of these polymers by topology. A theory is compared with the behavior of star- and theta-shaped poly(THF)s in size exclusion and interactive chromatography, and a good qualitative agreement between theory and experiment is observed. In particular, it is shown that in both SEC and interactive chromatography theta-polymers elute after the corresponding stars of the same molar mass. According to theory and experiment, chromatography under the critical and near-critical interaction conditions is especially promising for the separation of polydisperse macrocyclic polymers from their linear or branched analogues.