Perfluorosulfonate polymer

The first membranes to show significant potential and trigger the development of membrane electroly2ers were made from the perfluorosulfonate polymer called Nafion (40,41). 

Membrane cells are the state of the art chlor-alkah technology as of this writing. There are about 14 different membrane cell designs in use worldwide (34). The operating characteristics of some membrane cells are given in Table 3. The membranes are perfluorosulfonate polymers, perfluorocarboxylate polymers, and combinations of these polymers. Membranes are usually reinforced with a Teflon fabric. Many improvements have been made in membrane cell designs to accommodate membranes in recent years (35,36). 

Note Nafion is Du Font s brand name for perfluorosulfonate polymers. 

R. Yeo, Application of Perfluorosulfonated Polymer Membranes in Fuel Cells, Electrolysis, and Load Leveling Devices, in Perfluorinated Ionomer Membranes, A. Eisenberg and H.L. Yeager (eds), ACS Symposium Series Number 180, American Chemical Society, Washington, DC, pp. 453-473 (1982). 

In a H2/air fuel cell, the protons produced at the anode side need to be transferred to the cathode side to react with 02. This requires a proton transport electrolyte. Nafion membranes, composed of a perfluorosulfonated polymer, are the most commonly used polymer electrolyte membranes to conduct protons. The structure of the Nafion membrane is shown in Figure 1.5. Nafion can take on a... 

Wang et al. [55] have reported on the ability of the perfluorosulfonated polymer Nafion to solubilize SWCNTs and MWCNTs. They proposed that a homogeneous, well-distributed solution of Nafion/CNTs was obtained with 0.5 % v/v (in 0.05 M phosphate buffer pH 7.4) and 5% v/v polymer solution for SWCNTs and MWCNTs, respectively. A polished GCE was modified with 20 pL of a 2 mg/mL CNTs solution in 0.5 % w/w Nafion. The coating was allowed to... 

Hopfinger and Mauritz and Hopfinger also presented a general formalism to describe the structural organization of Nafion membranes under different physicochemical conditions. It was assumed that ionic clustering does not exist in the dry polymer. This assumption is applicable to the perfluorinated carboxylic acid polymer" but not the perfluorosulfonate polymers." They consider the balance in energy between the elastic deformation of the matrix and the various molecular interactions that exist in the polymer. 

Figure 10. Logarithm of self-diffusion coefficient vs. polymer-fraction function for 1200-EW perfluorosulfonate polymer, at 25°C. Na and Cs" lines without data points polystyrene sulfonate behavior. (Refs. 163 and 207 reprinted by permission of the publisher. The Electrochemical Society, Inc.)...

Self-diffusion coefficients of polyvalent cations in these perfluorinated ionomer membranes have not been reported. It can be inferred from the use of the sulfonate membranes as Donnan dialysis devices that transport of cations such as CuflT), Mg(II), and Al(III) under a concentration gradient is rapid. Also, column chromatographic separation of the alkaline-earth ion is readily accomplished with a powdered Nafion perfluorosulfonate polymer, which is again an indication of facile diffusion of these cations within the polymer phase. 

The majority of research which is discussed in this volume deals with the Nafion brand perfluorosulfonate polymers, manufactured by E. I. du Pont de Nemours and Co.. These materials were developed during the middle 1960 s, and have been available in various forms for study during the past few years. The synthesis and general properties of Nafion membranes are summarized... 

This high molecular weight polymer is melt fabricable and can be processed into various forms, such as sheets or tubes, by standard methods. Upon base hydrolysis, this resin is converted into Nafion perfluorosulfonate polymer ... 

Thermodynamic Studies of the Water— Perfluorosulfonated Polymer Interactions... 

Infrared Spectra of Perfluorosulfonated Polymer and of Water in Perfluorosulfonated Polymer... 

Applications of Perfluorosulfonated Polymer Membranes in Fuel Cells, Electrolyzers, and Load Leveling Devices... 

Yeo R S 1982 Applications of perfluorosulfonated polymer membranes in fuel cells, electrolyzers, and load leveling devices Perfluorinated lonomer Membranes ed A Eisenberg and H L Yeager (Washington, DC American Chemical Society) pp 453-73... 

I, 1980, 76, 2558-2574 L.Y. Levy, A. Jenard and H.D. Hurwitz, Hydration and ion-exchange process in carboxylic membranes. Part 1. Infrared spectroscopic investigation of the acid membranes, J. Chem. Soc. Trans. 1, 1982, 78, 29-36 M. Falk, Infrared spectra of perfluorosulfonated polymer and water in perfluorosulfonate polymer, Perfluorinated Ionomer Membranes, ed. A. Eisenberg, H.L. Yeager, ACS Symposium Series, American Chemical Society, Washington DC, 1982, p. 139 C. Heitner-Wirguin and D. Hall, An infrared study of an anion exchange membrane,... 

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