Title: A temperature-dependent implicit-solvent model of polyethylene glycol in aqueous solution,
Abstract: A temperature (T)-dependent coarse-grained (CG) Hamiltonian of polyethylene
glycol/oxide (PEG/PEO) in aqueous solution is reported to be used in
implicit-solvent material models in a wide temperature (i.e., solvent quality)
range. The T-dependent nonbonded CG interactions are derived from a combined
"bottom-up" and "top-down" approach. The pair potentials calculated from
atomistic replica-exchange molecular dynamics simulations in combination with
the iterative Boltzmann inversion are post-refined by benchmarking to
experimental data of the radius of gyration. For better handling and a fully
continuous transferability in T-space, the pair potentials are conveniently
truncated and mapped to an analytic formula with three structural parameters
expressed as explicit continuous functions of T. It is then demonstrated that
this model without further adjustments successfully reproduces other
experimentally known key thermodynamic properties of semi-dilute PEG solutions
such as the full equation of state (i.e., T-dependent osmotic pressure) for
various chain lengths as well as their cloud point (or collapse) temperature.