Molecular Dynamics Study of Structural and Flow properties of Polyelectrolyte-Grafted Nanoparticles in a Solution

Abstract

Polyelectrolytes have found applications in fuel cells, solar cells, membranes, etc. Here, we investigate the structural and flow properties of polyelectrolyte grafted nanoparticles (PENP) in a solution using coarse-grained molecular dynamic simulations. The degree of ionization (pH) and the concentration of PENP in solution are systematically varied. For low pH, the flow properties are dominated by grafted chain entanglements, while at high pH, the strong electrostatic repulsions between the ionized groups are the major factor. At intermediate pH, the hydrogen bonding between the ionized and non-ionized groups along with the concentration of PENP plays a significant role in dictating the solution viscosity. At low PENP concentrations, intra-particle hydrogen bonds are formed that lowers the viscosity, while at higher concentrations, inter-particle hydrogen bonds are formed enhancing the viscosity of the solution.