Polymer chains in good solvent facing impenetrable walls: What is the distance to the wall in lattice Monte Carlo simulations

Monomer density profile of polymer chains in the good solvent condition near an impenetrable wall was examined in lattice Monte Carlo simulation. It was found that a positive penetration depth γ is necessary for the density profile to follow the prediction of the scaling theory. In dilute solutions, γ was 0.13-0.22 of the lattice unit from a weak confinement to a strong confinement. With an increasing concentration, γ increased gradually to a value close to 0.36. These findings corroborate our hypothesis that the need of the positive γ and a greater γ at higher concentrations result from non-even chain transport due to a large difference in site occupancy, especially at higher concentrations.