Work

Interfacial solvation can explain attraction between like-charged objects in aqueous solution

Year: 2020

Type: article

Abstract: Over the past few decades, the experimental literature has consistently reported observations of attraction between like-charged colloidal particles and macromolecules in aqueous solution. Examples include nucleic acids and colloidal particles in the bulk solution and under confinement, and biological liquid-liquid phase separation. This observation is at odds with the intuitive expectation of an interparticle repulsion that decays monotonically with distance. Although attraction between like-charged particles can be rationalized theoretically in the strong-coupling regime, e.g., in the presence of multivalent counterions, recurring accounts of long-range attraction in aqueous solution containing monovalent ions at low ionic strength have posed an open conundrum. Here, we show that the behavior of molecular water at an interface-traditionally disregarded in the continuum electrostatics picture-provides a mechanism to explain the attraction between like-charged objects in a broad spectrum of experiments. This basic principle will have important ramifications in the ongoing quest to better understand intermolecular interactions in solution.

Source: The Journal of Chemical Physics

DOI: 10.1063/1.5141346

Authors: Alžbeta Kubincová, Philippe H. Hünenberger, Madhavi Krishnan

Institutions: ETH Zurich, Laboratory of Physical Chemistry, University of Oxford

Language: English

Topic: Electrostatics and Colloid Interactions

Subfield: Physical and Theoretical Chemistry

Field: Chemistry

Domain: Physical Sciences

Open Access status: green

Funders: Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung, H2020 European Research Council

Awards: A Combinatorial Computational Chemistry Approach to Force-Field Development, Control and measurement of single macromolecules in space and time