Enhancement of hydroxide conductivity by incorporating nanofiber-like palygorskite into quaternized polysulfone as anion exchange membranes

The natural hydrophilic nanofiber-like palygorskite (Pal) particles were incorporated into the quaternary am-monium functionalized polysulfone (QPSf) to prepare high performance anion exchange membranes. Due to the mutual compatibility between quaternary ammonium groups in quaternized polysulfone and hydrophilic Pal particles, a hydrophilic domain could aggregate, thereby forming a hydrophilic-hydrophobic microphase se-paration structure. Meanwhile, the small-angle X-ray scattering (SAXS) was utilized to characterize the hydro-philic ionic cluster domain in the composite membrane. The results showed that the corresponding average inter-domain spacing of the QPSf/Pal-0.5 membrane was about 30 nm. Then, the new composite membrane had not only highly efficient hydrophilic ion transport channels but also adjustable hydrophilic-hydrophobic mi-crophase separation structures. Compared with original quaternized polysulfone membranes, the hydroxide conductivity of the QPSf/Pal-0.5 membrane reached 93.0 mS.cm(-1) at 80 degrees C, increasing by 48%, while the methanol permeability was kept between 4.2 x 10(-7) and 5.8 x 10(-7) cm(2).s(-1).