Polyelectrolyte adsorption on a charged surface. Free energy calculation from Monte Carlo simulations using Jarzynski equality

C. F. NARAMBUENA; D. M. BELTRAMO; E. P.M. LEIVA

MACROMOLECULES

ACS Publications

Año: 2008 vol. 41 p. 8267 - 8274

0024-9297

In the present work we develop a Monte Carlo study of polyelectrolyte adsorption on a charged surface by means of a primitive model for the PE and the ions; the small ions are simulated in the Grand Canonical ensemble. Free energy profiles for the adsorption process were obtained using a generalization of Jarzynski equality, where a minimum was found close to surface. This minimum stems from a balance between the loss of configurational entropy by the PE chain upon adsorption, and the gain of translation entropy caused by the release of small ions. The results of the free energy of adsorption are compared with those from a previous work using mean field equations and simulated density profiles.