Multi-Resolution Simulations using the Integral Equation Coarse-Graining Method

We use the variable-level coarse-grained (CG) description of polymer melts to obtain the effective CG potentials (ECGPs) for multi-resolution simulations of pure polymer melts represented at various CG resolutions. Starting from the Integral Equation Coarse-Graining approach, we obtain the numerical and analytical ECGPs in the multi-resolution simulations that are different from the ECGPs in single-resolution simulations. Therefore, the composition, temperature, and density dependences of such ECGPs can be investigated. In particular, the ECGPs between the polymer melts, represented by n_bα blobs, decay slowly with a long tail characteristic scaling exponent of N_bα^1/4(φ_α+ (1-φ_α) (n_bα/n_bβ)³))^1/4, where φ_α is the volume mole fraction of species α, N_bα is the number of monomers in a given blob of type α, and β shows the other species. The ECGPs allow one to avoid any hybrid region in multi-resolution simulations while quantitatively producing the structural and thermodynamical properties of the related atomistic systems such as radial distribution function and pressure.