Semidilute Athermal Polymer Solutions near a Hard Wall

We have studied semidilute athermal polymer solutions near a hard wall extensively with Monte Carlo simulations. The details of the segment density profiles near the wall are shown for the first time. We have shown that in the semidilute regime the segment density near a wall has the form: φ(z) = φ(1 – e^–(z/ξ)m), where m is the exponent at small distance and φ and ξ are the bulk segment density and the bulk correlation length, respectively. This form fits remarkably well with the Monte Carlo simulations and was derived using an argument similar to Weibull’s for the failure of materials. We show m to be ~1.6 in agreement with De Gennes’ scaling prediction. The first-layer segment density, φ₁, from the simulations behaves as φ₁ ~ φ^2.2, similar to the bulk osmotic pressure. The radius of gyration, R_G, and the deduced correlation length, ξ, are also in accordance with the scaling predictions and the experiments.