STUDY OF THE MACROMOLECULAR POLARIZABILITY EFFECT ON THE POLYELECTROLYTE ADSORPTION ONTO SPHERICAL MACROIONS BY MONTE CARLO SIMULATIONS

Polyelectrolyte adsorption motivated numerous studies due to its relevance in biological systems and its wide range of technological applications, such as the flocculation step in water treatment, interactions involving proteins, and gene therapy. Experimental studies considering the interaction of polyelectrolytes with micelles and proteins have shown that the adsorption-desorption transition is characterized by an abrupt change in the solution's turbidity. Theoretical studies have demonstrated that increasing ionic strength leads to discontinuous transitions between adsorbed and desorbed states onto oppositely charged surfaces, characterized by different binding energy values and polyelectrolyte’s gyration radius. Particularly interesting is the effect of low macromolecular polarizability on the critical conditions, since the repulsive contribution of image charges can affect the adsorption stability. In this work, we used coarse-grained models and Monte Carlo simulations to examine the critical adsorption conditions of a polyelectrolyte chain onto a spherical macroion with different dielectric constants. We concluded that the variation of macroion's dielectric constant leads to significant effects in modeling this sort of system. The width of the polymer adsorbed layer is larger for macroions with a lower dielectric constant, requiring less salt concentration to cause the transition to a desorbed state.