Single Sodium-Ion Conducting Polymer Electrolyte Gels with Gyroidal Networks

Multiblock copolymers containing polar blocks of a sodium sulfonate group and nonpolar polyethylene blocks (precisely 12, 18, or 23 carbons) self-assemble into gyroid morphologies at an elevated temperature. Here, we place a single alkene group in the middle of each 18-carbon polyethylene block to enable a crosslinking reaction for maintaining the gyroid networks at ambient conditions. The morphological transitions of unsaturated polyethylene sodium sulfonates (uPES18Na) involve layered, gyroid, and hexagonally packed cylinder morphologies where gyroid morphologies exist at 100 – 140 °C. Crosslinked polyethylene sodium sulfonates (xPES18Na) are evident by the loss of C=C bonds and higher gel content with increasing reaction time. The X-ray scattering data show that xPES18Na exhibits less ordered gyroids than the uPES18Na. The xPES18Na of crosslinked gyroid networks can be swollen with a polar solvent, and the correlation between the morphologies and ionic conductivities will be discussed.