Bulk modulus of poly(ethylene oxide) simulated using the systematically coarse-grained model

In this work, the bulk modulus of the poly(ethylene oxide) (PEO) has been simulated using the dynamical stepwise compression procedure, for which the coarse-grained (CG) potentials are systematically parameterized by the multiscale scheme. It is demonstrated that the simulated bulk modulus and its temperature dependence compare well with the empirically calculated results, validating the CG potentials. Moreover, it is confirmed that the bulk modulus is closely related to the glass transition temperature (Tg), and thus the reliability in simulating the bulk modulus significantly depends upon the reliability in reproducing the Tg. Furthermore, good agreement is attributed to the adequate representability and transferability of the CG potentials, which are generally hard to be achieved at the same time. This work highlights that both can be simultaneously achieved by simply reproducing the pressure-volume-temperature properties. Together with great gains in computational efficiency, the multiscale scheme can find a wide application in simulating various polymer systems.