Improving the comprehensive performances of phosphonic acid functionalized poly(ether sulfone) by compositing with 1H-1,2,3-triazol-4-yl functionalized poly(ether sulfone)

•Phosphonic acid functionalized poly(sulfone ether) is synthesized by polycondensation.•Triazolyl functionalized poly(sulfone ether) is synthesized by polycondensation.•Performances of phosphonic acid functionalized poly(sulfone ether) are improved.•Acid–base composite proton exchange membrane is prepared.

The comprehensive performances of phosphonic acid functionalized poly(ether sulfone) (PES-PA) are improved by compositing with 1H-1,2,3-triazol-4-yl functionalized poly(ether sulfone) (PES-Tri). The PES-PA and PES-Tri are synthesized via the nucleophilic aromatic substitution (SNAR) polycondensation, respectively, of diethyl 2,5-dihydroxyphenylphosphonate and 4,4′-difuorodiphenylsulfone and of bisphenol A and 3,3′-diethynyl-4,4′-difluorodiphenylsulfone, and followed by hydrolysis or post-polymerization click reaction and deprotection reaction. In addition, two functionalized monomers, diethyl 2,5-dihydroxyphenylphosphonate and 3,3′-diethynyl-4,4′-difluorodiphenylsulfone are synthesized. Best comprehensive performances are achieved in the composite membrane consisting of 80% PES-PA and 20% PES-Tri by molar ratio of the functional structure units. At 100 °C and 90% RH (relative humidity), the proton conductivity of the composite membrane is 12.8 mS cm−1, about 1.8 times improvement compared with pristine PES-PA. In addition, the hydrophilicity and methanol permeability are alleviated, the water uptake is reduced from 31.3% to 16.1% at 100 °C and 90% RH and methanol permeability is reduced from 19.0 × 10−8 cm2 s−1 to 0.79 × 10−8 cm2 s−1 at 30 °C.

Graphical abstractThe comprehensive performances of phosphonic acid functionalized poly(sulfone ether) are improved by compositing of 20% triazolyl functionalized poly(sulfone ether).Figure optionsDownload full-size imageDownload as PowerPoint slide