Transferable potentials for coarse-grained simulations of block copolymer biomimetic membranes

We present a framework of minimal model transferable coarse-grained potentials for use in molecular dynamics simulations of amphiphilic block copolymer biomimetic membranes. Testing two, three, and five-bead models of polyethylene oxide polyethylethylene (PEO-PEE) polymer membranes, we show that values for membrane thickness and area per polymer chain obtained using the two-bead model are consistent with our experimental and previously published data. The calculated variation in membrane thickness ($d$) with hydrophobic molecular weight ($M_h$) conforms to a known scaling law ($d \sim M_{h}^{a}$). The same scaling exponent describes the area per polymer chain. We demonstrate that cross interactions can be represented using combining rules with the use of a scaling factor which is correlated with the difference in hydrophobicities of the interacting hydrophobic/hydrophilic monomers. In this way it becomes possible to rapidly simulate and screen new combinations of block copolymers with minimal potential development effort.