Partitioning of polymers into pores with surface interactions at dilute solution limit


The partitioning of a single polymer chain into a slit in a good solvent with different surface interactions is examined through Monte Carlo simulations from subcritical regime to adsorptive regime. The chain conformation in the subcritical regime is not perturbed by the surface interactions significantly. In the adsorptive regime, the conformation of the chain is strongly perturbed by the surface interactions. The confinement free energy in the two regimes maybe written in a uniform formula, βΔμconf ∼ c1N(a/D)xεw + c2N(a/D) 1/v with x ∼ 2.0 or larger in the subcritical regime and ∼1. 0 in the adsorptive regime, where v is the Flory exponent, D is the slit width, N is the chain length, a is the monomer size, and εw is the surface interaction energy between the polymer beads and the slit. This formula is valid for a long chain in the narrow slit in the subcritical regime or when the adsorption layer h > D in the adsorptive regime. A critical behavior occurs when εw is at the critical adsorption point and x = 1/v, then Δμconf will have little dependence on N or D. Higher order terms that are neglected in the above equation, however, may be present that could lead to a weak dependence of K on N and D even in the critical adsorption point. © 2003 Elsevier Ltd. All rights reserved.

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