Structure and Dynamics of Highly Segregated Ionizable Triblock co-Polymers in Solutions*

This study focuses on highly segregated ionizable triblock copolymers in the polyelectrolyte regime. These polymers are designed with electrochemical applications in mind such as high energy density capacitors, taking advantage of the unique properties of each block. In particular, we study tert-butyl polystyrene-b-polyethylene-r-propylene-b-sulfonated polystyrene (15k-15k-6k) with the goal of understanding the factors that control assembly. The high incompatibility of the blocks often drives formation of far from equilibrium states, posing a challenge to their processing. Using atomistic molecular dynamics simulations, we probe the assembly of this polymer in polar and nonpolar solvents and temperature to control these factors. We find that independent of the environment and the short polyelectrolyte segment, this triblock associates to form aggregates with the PSS segregated from the rest of the polymer, and the PEP forms nano-crystals. The nano-crystals melt at temperatures above T_g of PEP. However the PSS domains remain unperturbed and could be broken only by controlling the dielectric constant of the media. This talk will further expound on these factors in controlling assembly of highly segregated block copolymers.