A polymer chain trapped between athermal walls: Concentration profile and confinement force

We analyze the model problem of a single polymer chain in good solvent confined between athermal walls. Concentration profiles and forces are obtained by Monte Carlo simulations as the distance between the walls is decreased (and the solvent is allowed to drain from the system). The scaling of these quantities with chain length and wall separation, and the proportionality constant between surface concentration and force are in good agreement with recent theoretical predictions. The force and concentration exponents we find are modestly ( ≈ 10%) lower than previously predicted. This difference probably originates from the chain length not being sufficiently near the asymptotic limit. It could also indicate the need for carrying out the ε-expansion to higher order.