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DOE OSTI · 1834133

Overlap Concentration in Salt-Free Polyelectrolyte Solutions

Bollinger, Jonathan A.·Grest, Gary S.·Stevens, Mark J.·Rubinstein, Michael
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Abstract

For strongly charged polyelectrolytes in salt-free solutions, we use molecular dynamics simulations of a coarse-grained bead-spring model to calculate overlap concentrations c* and chain structure for polymers containing N = 10 to 1600 monomers. Over much of this range, we find that the end-to-end distance R* at c* increases faster than linearly with increasing N, as chains at the overlap concentration approach strongly extended conformations. This trend results in the overlap concentration c* decreasing as a stronger function of N than the classical prediction c* ~ N –2 . Finally, this stronger dependence can be fit either by a logarithmic correction to scaling or by an apparent scaling c* ~ N –m , with m > 2.

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37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRYchemical structureconformationcounterionspolyelectrolytespolymers

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Bollinger, Jonathan A., Grest, Gary S., Stevens, Mark J., Rubinstein, Michael. 2021-10-29. Overlap Concentration in Salt-Free Polyelectrolyte Solutions. https://doi.org/10.1021/acs.macromol.1c01491

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