Abstract
We investigate the structure of end-tethered polyelectrolytes using Monte Carlo simulations and molecular theory. In the Monte Carlo calculations we explicitly take into account counterions and polymer configurations and calculate electrostatic interaction using Ewald summation. Rosenbluth biasing, distance biasing, and the use of a lattice are all used to speed up Monte Carlo calculation, enabling the efficient simulation of the polyelectrolyte layer. The molecular theory explicitly incorporates the chain conformations and the possibility of counterion condensation. Using both Monte Carlo simulation and theory, we examine the effect of grafting density, surface charge density, charge strength, and polymer chain length on the distribution of the polyelectrolyte monomers and counterions. For all grafting densities examined, a sharp decrease in brush height is observed in the strongly charged regime using both Monte Carlo simulation and theory. The decrease in layer thickness is due to counterion condensation within the layer. The height of the polymer layer increases slightly upon charging the grafting surface. The molecular theory describes the structure of the polyelectrolyte layer well in all the different regimes that we have studied.
Original language | English (US) |
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Article number | 244902 |
Journal | Journal of Chemical Physics |
Volume | 126 |
Issue number | 24 |
DOIs | |
State | Published - 2007 |
Funding
One of the authors (O.J.H.) acknowledges support from the Department of Energy through the Computational Sciences Graduate Foundation program, Grant No. DE-FG02-97ER25308. Two authors (A.Z.P. and O.J.H.) acknowledge financial support from the Department of Energy, Office of Basic Energy Sciences (Grant No. DE-FG02-01ER15121), with additional support from ACS-PRF (Grant No. 38165-AC9). The authors thank Professor Alexandre Diehl for assistance with the electrostatic summation implementation. Another author (I.S.) acknowledges financial support from The National Science Foundation through Grant Nos. NSF-CTS-0338377 and NSF-NIRT 0403903.
ASJC Scopus subject areas
- General Physics and Astronomy
- Physical and Theoretical Chemistry