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Abstract
Electrophoretic (EP) mobility reversal is commonly observed for strongly charged macromolecules in multivalent salt solutions. This curious effect takes place, e.g., when a charged polymer, such as DNA, adsorbs excess counterions so that the counterion-dressed surface charge reverses its sign, leading to the inversion of the polymer drift driven by an external electric field. In order to characterize this seemingly counterintuitive phenomenon that cannot be captured by electrostatic mean-field theories, we adapt here a previously developed strong-coupling-dressed Poisson-Boltzmann approach to the cylindrical geometry of the polyelectrolyte-salt system. Within the framework of this formalism, we derive an analytical polymer mobility formula dressed by charge correlations. In qualitative agreement with polymer transport experiments, this mobility formula predicts that the increment of the monovalent salt, the decrease of the multivalent counterion valency, and the increase of the dielectric permittivity of the background solvent suppress charge correlations and increase the multivalent bulk counterion concentration required for EP mobility reversal. These results are corroborated by coarse-grained molecular dynamics simulations showing how multivalent counterions induce mobility inversion at dilute concentrations and suppress the inversion effect at large concentrations. This re-entrant behavior, previously observed in the aggregation of like-charged polymer solutions, calls for verification by polymer transport experiments.
Original language | English |
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Article number | 034503 |
Pages (from-to) | 1-14 |
Number of pages | 14 |
Journal | Physical Review E |
Volume | 107 |
Issue number | 3 |
DOIs | |
Publication status | Published - Mar 2023 |
MoE publication type | A1 Journal article-refereed |
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Dive into the research topics of 'Theoretical and computational analysis of the electrophoretic polymer mobility inversion induced by charge correlations'. Together they form a unique fingerprint.Projects
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LIBER Sammalkorpi: Life-like hybrid materials Sammalkorpi
Sammalkorpi, M. (Principal investigator), Hasheminejad, K. (Project Member), Holl, M. (Project Member), Kastinen, T. (Project Member), Morais Jaques, Y. (Project Member), Harmat, A. (Project Member) & Scacchi, A. (Project Member)
01/01/2022 → 31/12/2024
Project: Academy of Finland: Other research funding
Equipment
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Raw Materials Research Infrastructure
Karppinen, M. (Manager)
School of Chemical EngineeringFacility/equipment: Facility