Computer Simulations of Ionomer Self-Assembly and Dynamics

A molecular dynamic simulations on melts of telechelic chains of hard-sphere counterions were introduced to maintain charge neutrality. Bead-spring polymer model were used and augmented with Coulomb interactions. Small molecule counterions of the same size and nonpolar interactions as a chain monomer were included to maintain charge neutrality. Two definitions of the fraction of free counterions were considered to understand the role of counterions on the structure formation. It was found that ionomers self-assemble through a process where there is formation of ionic multiplets. It was also established by simulating with the counterions paired and unpaired that the intuition that dipolar interactions dominate the multipole assembly is well founded.