(648h) Zwitterionic Contribution to the Hydration Lubrication Dynamics of Poly(2-methacryloyloxyethyl phosphorylcholine)
In this work we explore the hydration structure and dynamics of pMPC polymers of varying chain lengths, pMPCn, in solution using molecular dynamics simulations. System setup and parameterization was aided by the open source Molecular Simulation and Design Framework6 (MoSDeF), developed at Vanderbilt. We compare bulk solvated pMPCn to poly(2-methacryloyloxyethyl phosphate)n (pMPn) to quantify the effect that the choline group has on hydrogen bonding between the pMPC polymer and water. When the choline group is removed, total hydrogen bonding between the pMP polymer and water is found to be reduced by approximately a factor of 2. The choline group plays an essential, but unintuitive role in the stabilization and increased hydration of the polymer through inter-monomer hydrogen bonding of the choline-phosphoryl groups. Although these interactions between the phosphoryl and choline groups limit possible water-phosphoryl hydrogen bonding, the âunfurlingâ effect these interactions have on the polymer exposes more hydration sites overall, leading to the pronounced hydration lubrication mechanism observed.
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