Hydration characteristics of blood-compatible poly(2-methoxyethyl acrylate) (PMEA) polymer chains at infinite dilution

PMEA polymer is an excellent non-thrombogenic polymer. Its non-thrombogenicity has been found due to the hydration water of the polymer. When the PMEA polymer comes in contact with water, it forms a complex interface consisting of nanoscale water-rich and polymer-rich domains. To understand the hydration behaviour of PMEA polymer in both domains, molecular dynamics simulations are employed to investigate the hydration characteristics of PMEA chains of different lengths at infinite dilution, as well as bulk polymer with experimental equilibrium water content, which are considered relevant to water-rich and polymer-rich domains, respectively. Investigations show that short PMEA chains behave like ideal polymer chains at infinite dilution, despite having a comb-like structure. The probability of water molecules around different oxygens in PMEA chains decreases with increasing chain length, reflecting a reduction in the hydrophilicity of the oxygen sites. Furthermore, the lifetime of hydrogen bonds between water and oxygen sites at infinite dilution is around 1–20 ps. By contrast, lifetimes of hydrogen bonds in the bulk polymer are the order of several hundred ps for alkoxy and methoxy oxygens and ns for carbonyl oxygen. The findings will aid in experimentation and the design of blood-compatible polymers.