Conformations and hydration structure of hydrophobic polyelectrolyte atactic poly(ethacrylic acid) in dilute aqueous solution as a function of neutralisation

TLDR: In this paper, the intermolecular structure and dynamics of polyethacrylic acid (PEA) in salt-free aqueous dilute solution at 25°C were studied via molecular dynamics simulations with explicit-solvent and explicit-ion description.

Abstract: Chain conformations, counter-ion structure, intermolecular hydrogen bonding structure and dynamics of atactic polyethacrylic acid (PEA) in salt-free aqueous dilute solution at 25°C are studied via molecular dynamics (MD) simulations with explicit-solvent and explicit-ion description for the first time The intermolecular structure was analysed by the radial distribution functions (RDF) for specific atom types between PEA chain, water molecules and Na+ counter-ions, as well as by the hydration near the PEA chain in the solvated system An increase in f provides an increase in 〈Rg〉 of the chain, consistent with the existence of the compact form of PEA The simulations show expansion for radius-of-gyration with increase in f, as expected for flexible polyelectrolytes under salt-free condition The extent of intermolecular hydrogen bonds (H-bonds) between PEA and water is enhanced by increase in f Chains having a higher counter-ion density show higher values of 〈Rg〉, influenced by intermolecular interactions