G-CG simulations were performed with the open-source software package ESPResSo . Short polymer chains consisting of 5 beads each were initially placed in a cubic box, and water was treated implicitely. The number of PEG molecules and the box dimensions were chosen to mimic the AA simulations. A generic bead-spring model derived from the Kremer-Grest polymer model was used to model the PEG chains. Each monomer was represented by a bead of mass m ≈ 39 u interacting via the purely repulsive Weeks-Chandler-Andersen potential , with an energy scale ϵ = k B T and a bead diameter σ = 0.355 nm. The chemical bonds between adjacent pairs of monomers were modeled using the finite extensibility nonlinear elastic (FENE) potential with magnitude k = 30 ϵ/σ 2 , maximal stretching length ∆r max = 1.5 σ, and equilibrium length r 0 = 0. Additionally, an angular potential