Theory of chromatography of partially cyclic polymers: Tadpole-type and manacle-type macromolecules

Abstract A theory of chromatography is developed for partially cyclic polymers of tadpole- and manacle-shaped topological structures. We present exact equations for the distribution coefficient K at different adsorption interactions; simpler approximate formulae are also derived, relevant to the conditions of size-exclusion, adsorption, and critical chromatography. Theoretical chromatograms of heterogeneous partially cyclic polymers are simulated, and conditions for good separation by topology are predicted. According to the theory, an effective SEC-radius of tadpoles and manacles is mostly determined by the molar mass M , and by the linear-cyclic composition. In the interactive chromatography, the effect of molecular topology on the retention becomes significant. At the critical interaction point, partial dependences K ( M l i n ) and K ( M r in g ) are qualitatively different: while being almost independent of M lin , K increases with M ring . This behavior could be realized in critical chromatography—for separation of partially cyclic polymers by the number and molar mass of cyclic elements.