Associating Groups Versus Molecular Architecture: Molecular Dynamics Insight Towards Blending Ionizable Linear-Star Polymers*

Associating groups to a polymer backbone has dramatic effects on the mobility and viscoelastic response. The associating group form assemblies whose lifetime depends on the strength of their interaction. Here, using molecular dynamics simulations, we probe the effects of strength of the interactions of associating groups on linear and star polymer melts and their blends. The polymer chains are described by a bead-spring model and the associating groups are incorporated in the form of associating beads on either the linear or star polymers or both with an interaction strength between associating beads that is varied from 1-20 k_BT. With increasing associating strength, the polymers associate into clusters of increasing size, independent of the polymer topography. These cluster act as crosslinkers which slow the chain mobility. Blends of chains with and without associating groups globally phase segregate even for relatively weak interaction between the associating groups.