Anion exchange membranes (AEMs) con

Anion exchange membranes (AEMs) continue to provoke interest as electrolytes in low temperature fuel cells.AEMs based on the triblock copolymer and polystyrene-b-poly(ethylene-co-butylene)-b-polystyrene (SEBS) canbe functionalized with different cationic groups. The coexisting anion, due to the possibility of different routes ofsynthesis, can also be varied. The hydrated morphology of SEBS functionalized with various cationic groupsprovides a suitable platform for understanding the mechanism of anion transport and the route to preparinghighly conductive and stable membranes. In this work, mesoscale dissipative particle dynamics (DPD) simulations were utilized to study the morphology of various SEBS-based ionomers: SEBS-trimethylammonium (SEBSTMA), SEBS- methylimidazolium SEBS-MIm and SEBS-trimethylphosphonium (SEBS-TMP) as a function of hydration levels. The morphology was transformed to perfect lamellae followed by disordered bicontiunous domains from perforated and interconnected lamellae as the hydration was increased from 4 to 20 H2O/headgroup. Perfect lamellae occur at λ = 8 for SEBS-TMP and at λ = 12 for SEBS-TMA and SEBS-MIm. Moreover,exclusive water domains were observed at high hydration levels for all systems. Large clusters of the water andhydrated OH– are formed when λ ≥ 8 for SEBS-TMP, SEBS-TMA, and SEBS-MIm. The choice of the functionalgroup was found to moderately affect the distribution of water but have little influence on the structure of thebackbone. The associated anion seemed to have a greater impact on the size of the exclusive water domainsrather than the cationic groups.