Polymer Adsorption & Surface Depletion

Polymer adsorption: when εₐ > εₐ,crit ≈ kT, a polymer layer builds up at the surface with thickness scaling as δ ~ aN^ν (ν=3/5 Flory). In the depletion regime (εₐ < 0), entropy loss near the wall creates a depletion zone of width ~ R_g. The concentration profile obeys the Edwards equation. The simulation shows a 2D random-walk chain; the profile panel shows φ(z) vs distance from wall.