Salt ions induced transport properties of poly(methacrylic acid) PMA in aqueous solutions studied by molecular dynamics simulations

Abstract

Abstract The detailed atomistic molecular dynamics simulations studies of multiple chain anionic polyelectrolyte poly(methacrylic acid) PMA was carried out to investigate the effect of monovalent salt i.e. NaCl on the transport properties such as self-diffusion coefficient of PMA, salt-ions and water molecules in dilute aqueous solutions. The concentration of NaCl was varied from dilute (0.01 M) to concentrated regime (1 M) and the self-diffusion coefficient of PMA, salt-ions and water molecules were calculated. The self-diffusion coefficient of PMA decreases with increase in NaCl concentration in agreement with experiments and previous reported simulations works. The salt ions i.e. Na+ and Cl- too shows a decrease in their self-diffusion coefficient values with NaCl concentration. The self-diffusivity of water molecules was found to be decrease in a linear manner with salt concentration. The salt-ions exhibits faster movement as compared to PMA and water on account of a higher self-diffusion coefficient.