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Updated: Jun 21, 2026

Controlling the Size, Shape and Stability of Supramolecular Polymers in Water
Published on: August 2, 2012
Counterions control the self-assembly of structurally persistent micelles: theoretical prediction and experimental
Christof M Jäger1,2, Andreas Hirsch3,2, Boris Schade4
1Computer-Chemie-Centrum and Interdisciplinary Center for Molecular Materials, Friedrich-Alexander Universität Erlangen-Nürnberg, Nägelsbachstr. 25, 91052 Erlangen (Germany), Fax: (+49) 9131-85-26565.
Abstract:
We show by molecular-dynamics (MD) simulations and cryo-transmission electron microscopy (cryo-TEM) experiments that the size and form of structurally persistent micelles formed by the T-shaped amphiphile 1 are controlled by the counterions. The two techniques reveal that the micelles are specifically stabilized by sodium counterions relative to potassium ions. Both the simulations and the cryo-TEM experiments suggest that the micelles are stabilized by strongly conserved hydrated contact ion pairs with sodium counterions but not with potassium ions. We suggest that the TEM is observing local high density due to hydrated carboxylate/sodium ion pairs at the surface of the micelle. A high concentration of such structures is found in MD simulations with sodium counterions, but not with potassium.
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