Overlap Concentration in Salt-Free Polyelectrolyte Solutions

Journal Article · Fri Oct 29 00:00:00 EDT 2021 · Macromolecules

DOI:https://doi.org/10.1021/acs.macromol.1c01491· OSTI ID:1834133

Bollinger, Jonathan A. ^[1]; Grest, Gary S. ^[1]; Stevens, Mark J. ^[1]; Rubinstein, Michael ^[2]

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1. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
2. Duke Univ., Durham, NC (United States)

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.

• Research Organization: Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE National Nuclear Security Administration (NNSA); National Science Foundation (NSF); National Institutes of Health (NIH)
• Grant/Contract Number: NA0003525
• OSTI ID: 1834133
• Report Number(s): SAND--2021-12780J; 700894
• Journal Information: Macromolecules, Journal Name: Macromolecules Journal Issue: 21 Vol. 54; ISSN 0024-9297
• Publisher: American Chemical Society
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
chemical structure
conformation
counterions
polyelectrolytes
polymers