Starting from the atomistic model, we build a CG model of a glycerol molecule using the recipe described in Marrink et al. Our CG model of glycerol has three polar beads to represent the three hydroxyl groups of the glycerol molecule (see SI Section S3 and Fig for the details). The beads were initially assigned type TP6 of the Martini 3 force field. However, we adjusted the Lennard-Jones parameters of the glycerol-glycerol interaction to get correct experimental glycerol density and the glycerol-bromide interaction to obtain bilayer structure consistent with atomistic simulations (see SI Table ).