Issue 32, 2017, Issue in Progress

Polyelectrolyte pKa from experiment and molecular dynamics simulation

Abstract

The pKa of a polyelectrolyte has been determined experimentally by potentiometric titration and computed using Molecular Dynamics (MD) constant pH (CpH) methodology, which allows the pKa of each titratable site along the polymer backbone to be determined separately, a procedure which is not possible by current experimental techniques. By using experimental results within the CpHMD method, the simulations show that the protonation states of neighbouring residues are anti-correlated so that the charges are well-separated. As found with previous simulation studies on model polyelectrolytes, the end groups are predicted to be the most acidic. CpHMD is shown to result in distinct polymer conformations, brought about by the range of protonation states changes along the polymer; this can now be used in the design of pH-responsive polymers for, amongst other applications, additive formulation and drug delivery devices.

Graphical abstract: Polyelectrolyte pKa from experiment and molecular dynamics simulation

Supplementary files

Article information

Article type
Paper
Submitted
05 Dec 2016
Accepted
23 Mar 2017
First published
05 Apr 2017
This article is Open Access
Creative Commons BY license

RSC Adv., 2017,7, 20007-20014

Polyelectrolyte pKa from experiment and molecular dynamics simulation

M. S. Bodnarchuk, K. E. B. Doncom, D. B. Wright, D. M. Heyes, D. Dini and R. K. O'Reilly, RSC Adv., 2017, 7, 20007 DOI: 10.1039/C6RA27785C

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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