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

POLYMER

卷:212

Article

Narambuena, Claudio F.^1,2  Blanco, Pablo M.^3,4  Rodriguez, Adrian⁵  Rodriguez, Diego E.⁵  Madurga, Sergio^3,4  Garces, Jose L.^6,7  Mas, Francesc^3,4 

[1] Univ Tecnol Nacl UTN FRSR, Fac Reg San Rafael, RA-5600 Mendoza, Argentina

[2] Consejo Nacl Invest Cient & Tecn, Inst Fis Aplicada INFAP, RA-5600 Mendoza, Argentina

[3] Barcelona Univ UB, Phys Chem Unit, Mat Sci & Phys Chem Dept, Barcelona 08028, Catalonia, Spain

[4] Barcelona Univ UB, Res Inst Theoret & Computat Chem IQTCUB, Barcelona 08028, Catalonia, Spain

[5] Univ Tecnol Nacl, Fac Reg Neuquen, Plaza Huincul, RA-8318 Neuquen, Argentina

[6] Lleida Univ UdL, Tech Sch Agr Engn, Dept Chem, Lleida 25003, Catalonia, Spain

[7] Lleida Univ UdL, AGROTECNIO, Lleida 25003, Catalonia, Spain

关键词: Weak polyelectrolytes;    Adsorption;    Charge reversion;    Charge surface;    Constant pH simulation;    Monte Carlo;   

DOI  :  10.1016/j.polymer.2020.123170

来源: Elsevier

【 摘 要 】

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 non-monotonic behavior, with the appearance of a maximum close to the intrinsic pK-value of the PE titratable groups. The apparent pK(a)(0)-value of the PE chains shows a nontrivial 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 > pK(a)(0 )+ 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.

【 授权许可】

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