Ionizable Triblock co-Polymers Solutions under Extensional Flow

Tethering polymers with different properties into one macromolecule are a promising venue for designing materials. Adding ionizable groups to the backbone of one blocks opens up many current and potential applications, including fuel cell membranes and high-density capacitors. However, because of the high glass transition temperature of the ionizable blocks, these polymers are often processed from solvents under flow. Using large scale fully atomistic molecular dynamics simulations, this study focuses on the response of ionizable triblock copolymers in the ionomer and polyelectrolyte regimes under extensional flow. Specifically, we study tert-butyl polystyrene-b-polyethylene-r-propylene-b-sulfonated polystyrene (15k-15k-6k) in toluene. In the quiescent state, the polymer assembles into micelles with the ionizable block in the core and the other two blocks in the corona. Surprisingly, the PEP blocks form semi-crystalline bundles in the corona at room temperature. This study will present the flow response of this triblock copolymer at temperatures above and below the temperature where the PEP bundles melt. Specifically, we correlate the dynamics of the ionic clusters and the unraveling of the PEP bundles as a function of flow rate.