Mr. Lee's Research Review

Synthesis and Characterization of Multiblock Copolymers with Hydrophilic-Hydrophobic Sequences as Novel Proton Exchange Membranes

      Among the various types of fuel cells, polymer electrolyte membrane fuel cells (PEMFCs) have been the most extensively explored due to their promise as an ideal candidate for mobile, automotive, and stationary applications. Currently used proton exchange membranes are perfluorinated sulfonated ionomer membranes such as Nafion. However, Nafion type PEMs easily lose their electrochemical and mechanical properties at high operation temperatures ( > 80 °C) which are essential for practical fuel cell operations. Recently, PEMs based on hydrophilic-hydrophobic multiblock copolymers are being considered strong candidates which can avoid the disadvantages of Nafion type PEMs due to their unique membrane properties. Once the block copolymers are cast into membranes, they exhibit nano-phase separated morphologies and well-connected ionic hydrophilic phases, which can facilitate high proton conduction even under low humidity conditions while the well-connected hydrophobic phase provides dimensional stability. In the McGrath group, I have been exploring various multiblock copolymer systems with different chemical components. A representational multiblock copolymer and its morphology are shown here and here.

1. Lee, Hae-Seung; Badami, Anand S.; Roy, Abhishek; McGrath, James E.; "Segmented sulfonated poly(arylene ether sulfone)-b-polyimide copolymers for proton exchange membrane fuel cells. I. Copolymer synthesis and fundamental properties", Journal of Polymer Science, Part A: Polymer Chemistry (2007), 45(21), 4879-4890.
2. Anand S. Badami, Abhishek Roy, Hae-Seung Lee, Yanxiang Li, and James E. McGrath, “Morphological Investigations of Disulfonated Poly(arylene ether sulfone)-b-Naphthalene Dianhydride-Based Polyimide Multiblock Copolymers as Potential High Temperature Proton Exchange Membranes”, Journal of Membrane Science, 2008 (submitted).

Please send any questions or comments to the webmaster.

Updated 5/13/2008