Structure and properties of sulfonated polysulfone-poly-dopamine-ZrO₂ hybrid composite proton exchange membrane

The main obstacle of wide commercialization of proton exchange membrane is to maintain the high conductivity and low swelling ratio of proton exchange membrane at higher temperature under fully hydrated state. In order to solve this issue, by using poly-dopamine (PDA) as an intermediate layer, ZrO₂ was formed on the commercial sulfonated polysulfone (PSF) porous membrane matrix, a facial approach of preparing well performed composite proton exchange membrane was proposed. The influence of PDA deposition conditions and ZrO₂ mineralization process on the surface morphology and element distribution of PSF-PDA-ZrO₂ composite membrane were investigated. The PSF-PDA modified membrane with PDA deposition time of 5 h was selected for mineralization. It is found that the content of Zr element on the surface mineralized layer of PSF-PDA-ZrO₂ composite membranes is significantly increased with increasing mineralization time. The water uptake, swelling ratio and proton conductivity of PSF-PDA-ZrO₂ composite membrane were tested. The results show that the surface of ZrO₂ mineralized layer significantly inhibits the swelling ratio of PSF-PDA-ZrO₂ composite membranes at higher temperature compared with PSF porous membranes, and the swelling ratio of composite membranes gradually reduces with the increase of ZrO₂ mineralization time. The proton conductivity of PSF-PDA-ZrO₂ composite membranes with mineralization time for 1 h, 5 h, 12 h and 24 h is higher than that of the pure PSF porous membrane, and the conductivity of the PSF-PDA-ZrO₂ composite membranes decreases gradually with the increase of mineralization time. The proton conductivity of PSF-PDA-ZrO₂ composite membrane after PDA deposition for 5 h and mineralization for 1 h is up to 0.117 Scm^-1 at 90℃, which is 2.5 times of the PSF porous basement membrane.