STUDY OF THE POLYELECTROLYTE ADSORPTION ONTO HIGHLY CHARGED SURFACES BY MONTE CARLO METHOD

Polyelectrolyte adsorption onto highly oppositely charged surfaces provides relevant information to analyze electrostatic interactions between macromolecules with considerable large flexibility differences. Some systems with these characteristics include polymer solutions, both natural and synthetic, as well as micelles, proteins, dendrimers, and intrinsically disordered proteins, along with their biological partners. Experimental studies have shown that the salt and pH variation leads to abrupt change in the solution's turbidity. Theoretical studies 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. Another particularly interesting result was the unified theory that showed how the critical parameters are affected by geometry, led by applying the WKB method to analytically solve the Edwards equation in plane, spherical, and cylindrical geometries. Moreover, recently we showed that charge renormalization can be used to study the adsorption of polyelectrolytes on highly charged surfaces since it considers the non-linear screening that occurs at higher charge densities. In this work, we employ coarse-grained models and Monte Carlo Metropolis simulations to examine the critical adsorption conditions and the effects of electrostatic persistence length using non-linear Poisson-Boltzmann solutions to describe monomer-surface interactions. We concluded that the geometry influences the critical salt concentration. At high salinity, the effect of saturation of the renormalized charge observed when we consider the charge renormalization is also observed from Monte Carlo simulations.