Interfaces and Interphases in Dense, Polydisperse Living Polymer Systems: A Comparison Between Computer Simulation and Self-Consistent Field Theory

Abstract

Using particle-based simulations of a soft, coarse-grained model and self-consistent field theory (SCFT) we investigate the properties of dense living polymer systems in bulk and thin films. Reversible bond formation and breaking is controlled by a bonding free energy, E-b, and results in a polydisperse melt of linear flexible polymers and rings. For bulk systems we observed an exponential decay of the molecular weight distribution for all but the smallest molecular weight. The latter affect stems from the indistinguishability of the two bonding sites of a living monomeric unit. Under confinement into a film, the presence of the solid substrates gives rise to a redistribution of living monomers and chains in the wide interphase and, therefore, alters the local molecular weight distribution and local mean molecular weight. Additionally, we find that the presence of a solid substrate enhances the formation of rings with high molecular weight by reducing the dimensionality of ring living polymers in the vicinity of solid substrate and increasing the probability of two chain ends belonging to the same linear living polymer chain to meet with each other. The result of particle-based simulations and numerical self-consistent field theory are compared and, although there are differences of the two descriptions in the narrow interface, qualitative agreement is found in the wide interphase.