Nafion
“Nafionis a sulfonated tetrafluoroethylene based fluoropolymer-copolymer discovered in the late 1960s by Walther Grot of DuPont. It is the first of a class of synthetic polymers with ionic properties which are called ionomers. Nafion's unique ionic properties are a result of incorporating perfluorovinyl ether groups terminated with sulfonate groups onto a tetrafluoroethylene (Teflon) backbone. Nafion has received a considerable amount of attention as a proton conductor for proton exchange membrane (PEM) fuel cells because of its excellent thermal and mechanical stability.”
“The chemical basis of Nafion's superior conductive properties remain a focus of research. Protons on the SO3H (sulfonic acid) groups "hop" from one acid site to another. Pores allow movement of cations but the membranes do not conduct anions or electrons. Nafion can be manufactured with various cationic conductivities.”
Fluorinated Polymers
Nafion Films
Polymers /Resins
Polytetrafluoroethylene (PTFE)
Recent Journal Articles
1/28/2011
Biaxial elastic–viscoplastic behavior of Nafion membranes
(529-539) Polymer 52 #2 (2011)
Silberstein, Pillai and Boyce of the Massachusetts Institute of Technology, Massachusetts determined the mechanical behavior including linear elasticity followed by a highly non-linear transition to yield followed by post-yield strain hardening with highly non-linear unloading and reloading; these features were each quantitatively dependent on the biaxiality of the loading conditions. The constitutive model was found to successfully quantitatively predict the loading behavior and its dependence on biaxiality. The constitutive model was also found to predict the magnitude of the yield shoulder during unloading and reloading, but to underestimate the gradual nature of both the forward and reverse plastic deformation processes as well as the strain recovery at zero load. These errors are consistent with those seen in the uniaxial model indicating that the framework used to incorporate the uniaxial behavior into a three dimensional model is capable of predicting the biaxial deformation response of the membrane. (RDC 1/27/2011)