Состоится научный доклад "Developing theoretical foundations of polymer chromatography at critical conditions with molecular simulations". Выступит Dr Aleksey Vishnyakov, Center for Computational and Data-Intensive Science and Engineering (CDISE) Skolkovo Institute of Science and Technology.

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Abstract

Adsorption of chain molecules on nanostructured surfaces and within nanoscale pores is the key mechanism of chromatographic separation and characterization of polymers, which is commonly employed in almost all branches of chemical and petroleum industries, as well as in biology and medicine. The two main thermodynamic factors guiding the retention of polymers in nanoporous chromatographic columns are (1) entropic penalty cause by confinement of the polymer coil near solid walls (2) enthalpy loss due to monomer adsorption. Both contributions depend on adsorption field, porous structure and the solvent, and both increase with the polymer length. At conditions where they effectively cancel each other, the elution becomes length independent, which gives an opportunity to resolve an important practical problem: separate polymers by their chemical structure rather than molecular weight.

The talk describes a recent effort to explore the free thermodynamics and transport of chain molecules in nanoporous matrices using Monte Carlo simulations in conjunction with Fokker-Planck formalism. For this purpose, we designed a new Monte Carlo technique for calculation of free energies of confined polymers called the polymer gauge cell method. Based on the free energy landscape of confined polymers for varying molecular weight, pore size and adsorption field, we predict polymer transport in the porous matrices that form the chromatographic columns for polymer separation. Finally, the results are employed for thermodynamic analysis of critical conditions of polymer adsorption and chromatographic separation.