Structural and Dynamical Properties of Water and Salt ions in Confined Geometries of Block Copolymers

Understanding the transport properties of water and salt ions in confined geometries of block copolymers is crucial for water purification including others nanotechnology and biotechnology. Here, we investigate the local diffusivities along with supporting structural properties of water and salt (Na⁺ and Cl^-) ions in the different regions from the pore with varieties of sizes made by morphologies of liner triblock copolymers such as lamella, cylinder, and gyroid using dissipative particle dynamics (DPD) mesoscale simulations. Besides, we extend our study to investigate the water and salt permeability through the membranes. Our results suggest that diffusivities of water and salt ions in the different region of pores are different than in the bulk phases. Under the confined conditions, the mobility of water and salt ions are perturbed by the additional interaction forces that arise from the blocks that have preferable water selectivity, which ultimately reduces the local molecular diffusion. Further, the geometries of block copolymers with different sizes of pore also influence the structural and dynamical properties of water and salt ions.