ABA Triblock Brush Polymers: Synthesis, Self-Assembly, Conductivity, and Rheological Properties

The synthesis, self-assembly, conductivity, and rheological properties of ABA triblock brush polymers (BBCPs) with grafted polystyrene (A block, NPS = 21) and poly(ethylene oxide) (B block, NPEO = 45) side chains are reported. Two backbone molecular weights (NA:NB:NA = 11:78:11 and 15:119:15) were investigated with lithium bis(trifluoromethane)sulfonimide (LiTFSI) doping ratios 2 ≤ EO:Li+ ≤ 20. Blends with 2 ≤ EO:Li+ ≤ 10 suppress PEO crystallization and self-assemble into hexagonally packed cylinders of the minority gPS component. Conductivity is on the order of 10–3 S/cm at 105 °C with a corresponding elastic modulus ca. 104 Pa. The optimum conductivity occurs at a blend ratio near 10:1 EO:Li+, similar to that reported for linear block copolymer analogues.