TY - JOUR
T1 - Sulfonated polymers containing polyhedral oligomeric silsesquioxane (POSS) core for high performance proton exchange membranes
AU - Zhang, Jie
AU - Chen, Fang
AU - Ma, Xiaoyan
AU - Guan, Xinghua
AU - Chen, Dongyang
AU - Hickner, Michael A.
N1 - Publisher Copyright:
© 2015 Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
PY - 2015/6/15
Y1 - 2015/6/15
N2 - A series of POSS containing star-shaped block copolymers were synthesized by atom transfer radical polymerization (ATRP), with POSS-(Cl)8 as initiator, polymethyl methacrylate as the first building block, and polystyrene as the second building block. Sulfonation of the polystyrene block yielded star-shaped ionic polymers POSS-(PMMA-b-SPS)8 that were evaluated as proton exchange membranes (PEMs) subsequently. Under low relative humidities (RHs), the PEM with longer SPS block exhibited higher proton conductivity than the PEM with shorter SPS block when compared at same hydration number (λ) conditions, which was attributed to the better connected hydrophilic domains of the former as evidenced by electron microscopes. However, this conductivity trend for the two PEMs was reversed at 100% RHs. Low field nuclear magnetic resonance analysis revealed that the PEM with shorter SPS block had more loosely bonded water than the PEM with longer SPS block at 100% RH, giving an explanation of why the conductivity trend was reversed. This study suggested that both ionic domain structure and water-polymer interaction are important parameters for achieving high proton conductivities.
AB - A series of POSS containing star-shaped block copolymers were synthesized by atom transfer radical polymerization (ATRP), with POSS-(Cl)8 as initiator, polymethyl methacrylate as the first building block, and polystyrene as the second building block. Sulfonation of the polystyrene block yielded star-shaped ionic polymers POSS-(PMMA-b-SPS)8 that were evaluated as proton exchange membranes (PEMs) subsequently. Under low relative humidities (RHs), the PEM with longer SPS block exhibited higher proton conductivity than the PEM with shorter SPS block when compared at same hydration number (λ) conditions, which was attributed to the better connected hydrophilic domains of the former as evidenced by electron microscopes. However, this conductivity trend for the two PEMs was reversed at 100% RHs. Low field nuclear magnetic resonance analysis revealed that the PEM with shorter SPS block had more loosely bonded water than the PEM with longer SPS block at 100% RH, giving an explanation of why the conductivity trend was reversed. This study suggested that both ionic domain structure and water-polymer interaction are important parameters for achieving high proton conductivities.
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U2 - 10.1016/j.ijhydene.2015.02.090
DO - 10.1016/j.ijhydene.2015.02.090
M3 - Article
AN - SCOPUS:84929282698
SN - 0360-3199
VL - 40
SP - 7135
EP - 7143
JO - International Journal of Hydrogen Energy
JF - International Journal of Hydrogen Energy
IS - 22
ER -
