Correlating the Dependability of Nanoparticle Dispersion with the Presence of Matrix Polymer in Nanoparticle Composites Gr

Abstract

Grafting of polymers on the surface of nanoparticles (NPs) instead of surface coating of nanoparticle with polymers have been shown to lead to better dispersion of nanoparticles is the polymer nanocomposites (PNC). This is due to better steric effect induced by the grafted polymer chains which enhances the dispersion of the nanoparticles in the system. However, although there is a better dispersion of the nanoparticles in the PNCs, which leads enhanced mechanical strength of the PNC material, the presence of the free polymer chains reduces the dispersibility of the NPs due to the entanglements that occurs between the free polymer chains (matrix polymers) and the grafted polymer chains. Thus, some form of aggregation is still experienced by the NPs in the PNCs. We seek to show that by systematically reducing the concentration of the matrix polymers in the system, more dispersion of the nanoparticle can be achieved. Coarse-grained molecular dynamics simulations using LAMMPS parallel MD packages is used in simulating a system which includes solvents, matrix homopolymer chains and nanoparticles grafted with linear polymer chains (PGNPs). Three systems were developed with different but related compositions namely: (1) Solvent, matrix polymers and PGNPs, (2) Solvent and PGNPs, (3) Solvent and PGNPs with longer PGNPs than the previous two systems. The mean displacement of the nano-particles in the systems will be calculated to understand the diffusivity of the nano-particles. This will be done to shed light on some dynamic properties of the nano-particles in the system.