Effect of different imidazole group positions on the hydroxyl ion conductivity

Hydroxyl ionic conductivities of anion exchange membrane with three different imidazolium group positions were studied. Models of Poly (aryl ether oxadiazole) anion-exchange membranes with the same degree of functionality were investigated by molecular dynamics simulation. Mean square displacement (MSD) was applied for hydroxyl ions, H2O and methanol diffusion coefficient calculation. The distance of N+-N+, N-OH-O was analyzed using radial distribution function (RDF). Simulation results shown that hydroxyl ions had more chances to appear around imidazole radical groups. The hydroxyl ionic conductivity of Line-type, Meta-type and Diagonal-type respectively were 7.74 × 10−2 S·cm−1, 4.66 × 10−2 S cm−1 and 1.78 × 10−2 S cm−1. The diffusion rate of CH3OH molecules had the same trends with OH− particles, reducing from the Line-type to Diagonal-type.