2002/11/30 by Vincent Krakoviack, V. Krakoviack, J. P. Hansen +2
Chemistry · Engineering · Materials Science · Physics and Astronomy · #Electrostatics and Colloid Interactions #Material Dynamics and Properties #Phase Equilibria and Thermodynamics #cond-mat.soft #cond-mat.stat-mech
paper · pdf · doi:10.1103/physreve.67.041801
published as Phys. Rev. E 67, 041801 (2003) · 15 pages, 12 figures (one added in revised version), revTeX4
arxiv created 2003/02/26 · openalex publication_date 2003/04/25 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Solutions of interacting linear polymers are mapped onto a system of "soft" spherical particles interacting via an effective pair potential. This coarse-graining reduces the individual monomer-level description to a problem involving only the center of mass (c.m.) of the polymer coils. The effective pair potentials are derived by inverting the c.m. pair distribution function, generated in Monte Carlo simulations, using the hypernetted chain closure. The method, previously devised for the self-avoiding walk model of polymers in good solvent, is extended to the case of polymers in solvents of variable quality by adding a finite nearest-neighbor monomer-monomer attraction to the previous model and varying the temperature. The resulting effective pair potential is found to depend strongly on temperature and polymer concentration. At low concentration the effective interaction becomes increasingly attractive as the temperature decreases, eventually violating thermodynamic stability criteria. However, as polymer concentration is increased at fixed temperature, the effective interaction reverts to mostly repulsive behavior. These issues help to illustrate some fundamental difficulties encountered when coarse-graining complex systems via effective pair potentials.