Non-monotonic behavior of weak-polyelectrolytes adsorption on a cationic surface: a Monte Carlo simulation study

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Data de publicació
2021Autor/a
Narambuena, Claudio F.
Blanco, Pablo M.
Rodriguez, Adrian
Rodriguez, Diego E.
Madurga, Sergio
Mas i Pujadas, Francesc
Citació recomanada
Narambuena, Claudio F.;
Blanco, Pablo M.;
Rodriguez, Adrian;
Rodriguez, Diego E.;
Madurga, Sergio;
Garcés, Josep Lluís;
Mas i Pujadas, Francesc;
.
(2021)
.
Non-monotonic behavior of weak-polyelectrolytes adsorption on a cationic surface: a Monte Carlo simulation study.
Polymer, 2021, vol. 212, núm. 6, p. 1-41.
https://doi.org/10.1016/j.polymer.2020.123170.
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In this work, the weak polyelectrolyte (PE) adsorption on a strong cationic surface is
studied with constant pH Monte Carlo simulations using a coarse-grained model. When a large
number of PE chains is added to the system, the PE adsorbed amount vs pH curve exhibits a nonmonotonic behavior, with the appearance of a maximum close to the intrinsic p
-value of the
PE titratable groups. The apparent p
-value of the PE chains shows a non-trivial tendency
depending on the pH-value and the surface coverage degree. In increasing the pH-value, the
small anions that accompany the cationic surface are replaced by PE chains and small cations.
For pH > ~ p
+ 1, an evident charge reversion of surface is observed. These results are
explained analyzing the interplay between the attractive and repulsion electrostatic interactions
between the different components of the system (inter- and intra-charged monomers of PE
chains, the strong cationic surface and small ions) and their effects on the PE chain ionization.