Polymerization of -sulfonated

Wang, R, Hickner, M., Kim, Y. S., Zawodzinski, T. A. and McGrath, J. E. 2002. Direct polymerization of sulfonated poly(arylene ether sulfone) random (statistical) copolymers Candidates for new proton exchange membranes. Journal of... 

Liu W, Cholli AL, Kumar J, Tripathy S, Samuelson L (2001) Mechanistic study of the peroxidase-catalyzed polymerization of sulfonated phenol. Macromolecules 34(11) ... 

The sodium salts and the acids of poly-3(2-ethanesul-fonate) thiophene and poly-3-(4-butanesulfonate) thiophene are the first known examples of water soluble CPs many other examples of water-soluble, self-doped CPs are given in recent reviews. Indeed, it is well known that the incorporation of highly soluble sulfonate groups on the CP backbone is a common method of achieving water solubility in a doped CP. The two most popular routes are the use of sulfonated polymeric dopants and the polymerization of sulfonated monomers. 

Z. Ogumi, Y. Uchimoto and Z. Takehara, A new ultra-thin fluorinated cation exchange film prepared by plasma polymerization. J. Electrochem. Soc., 1990, 137, 3319-3320 C.J. Brumlik, A. Parthasarathy, W. Chen and C.R. Martin, Plasma polymerization of sulfonated fluorochlorocarbon lonomer films, J. Electrochem. Soc., 1994, 141, 2273-2279. 

A second method of introducing sulfonate groups is accomplished by deprotonating polyaniline base and reacting with a sultone, i.e., 1,3-propanesultone [22]. This gives rise to an N-substituted polyaniline derivative that is water soluble. Another route involves the polymerization of sulfonated aniline monomer such as sodium salt of diphenylaminesulfonic acid [23]. 

Recent efforts in the synthesis of sulfonated aromatic polymers are directed to the polymerization of sulfonated monomers (such as (b), (d), (g), (j), (k), and (1) shown in Scheme 3) [14,15,53,54,96-102] or coupling reactions of sulfonated compoimds with fimctional groups attached to a polymer backbone [ 103,104]. In post-sulfonation, attachment of the sulfonic acid group is restricted to the activated position ortho to the aromatic ether bond, as indicated in Scheme 4a, while in direct polymerization of sulfonated monomers, the sulfonic acid groups are attached to the deactivated site on the ring (Scheme 4b). An enhancement of stabUity toward desulfonation and a modestly higher acidity are expected for the structure shown in Scheme 4b. Recently, polymerization of sulfonated monomers was also used to obtain sulfonated polysulfone (m) via oxidation of a sulfonated polysulfide-polysulfone copolymer [105]. 

The development of polyaryls, in particular polyetherketones (PEEK), as a substitute of perfluorinated polymers was mainly based on cost and stability considerations [1]. Sulfonated polyetherketones has been found to be durable under fuel cell operation conditions over several thousand hours [185]. Victrex Company is the main producer of PEEK polymer and its sulfonation can be performed directly on the polymer backbone or by polymerization of sulfonated monomers [7]. Hoechst-Aventis and Eumatech commercialize sulfonated PEEK (sPEEK) and sulfonated poly(phtalazinone ether ketone) (sPPEK) membranes for fuel cell applications [3]. 

Polymer membranes have low proton conductivity until they contain enough proton conductive functional groups, e.g., sulfonic acid, in polymer backbones or side chains. Sulfonic acid in polymer chains shows a high dissociation constant, resulting in high proton conductivity in aqueous environments compared with other acids therefore, most DMFC membranes use the sulfonic moiety as the proton transfer medium. Sulfonation methods of polymer membranes are generally classified as post-sulfonation in the presence of polymers and in situ sulfonation through co-polymerization of sulfonated monomers and nonsulfonated monomers. 

Sulfonated phenol-formaldehyde polymer is the first hydrocarbon-based polymer membrane in the literature. The phenolic polymer membrane was prepared by condensation polymerization of sulfonated phenol with formaldehyde, but the sulfonated phenolic polymer had low chemical and mechanical stability for fuel cell applications. 

Poly(ether ether) ketone (PEEK) and poly(ether ether ketone ketone) (PEEKK) are highly stable polymers with good potential for application in DMFCs [10,17,18]. They are semicrystalline and display excellent chemical and thermal stability. They may be sulfonated through direct polymerization of sulfonated monomers or by postsulfonation, the latter again leading to materials with less tightly controlled degree and location of sulfonation, but with the attraction that it is a simple and low-cost approach [19]. 

This is at least partly due to the wide range of reactants that are commercially available for sulfonation. Besides direct sulfonation by electrophUic substitution reactions with, for example, fuming sulfuric acid, sulfonated ionomers have been also accomplished by chemical grafting [20,21] and by direct polymerization of sulfonated monomers [22-27]. 

SPIs can be synthesized by either post-sulfonation of a polyimide or by direct polymerization of sulfonated monomers. While the first method is largely used for the suhbnation of aromatic polymers such as poly(aryl ether ether ketones) [41-44] or polysuhbnes [37], it is scarcely used to synthesize SPIs,... 

One Step Polymerization of Sulfonated Polystyrene Films in a Dielectric Barrier Discharge. Plasma Process. PolyrtL, Vol. 7, pp. 836-845 Michel, M. Bour, J. Petersen, J. Amoult, C. Ettingshausen, F. Roth, C Ruch, D. (2010). 

Victrex Company is the main producer of the PEEK polymer in the market now and its sulfonation is generally performed via sulfonic acid groups (SO3H), which are directly introduced onto the polymer backbones, by modification or by polymerization of sulfonated monomers. Sulfonated PEK, PEEK, PEEKK, and PEEK-WC show interesting behaviors in terms of wettability, water flux, antifouling capacity, low fuel... 

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