Adsorption of cationic polyions onto a hydrophobic surface in the presence of Hofmeister salts

Abstract

We study, using extensive Monte Carlo simulations, the behavior of cationic polyelectrolytes near hydrophobic surfaces in solutions containing Hofmeister salts. The Hofmeister anions are divided into kosmotropes and chaotropes. Near a hydrophobic surface, the chaotropes lose their solvation sheath and become partially adsorbed to the interface, while the kosmotropes remain strongly hydrated and are repelled from the interface. If the polyelectrolyte solution contains chaotropic anions, a significant adsorption of polyions onto the surface is also observed. On the other hand, the kosmotropic anions have only a small influence on polyion adsorption. These findings can have important implications for exploring the antibacterial properties of cationic polyelectrolytes.