Synthesis of Proton-conducting Electrolytes Based on Poly(vinylidene fluoride-co-hexafluoropropylene) via Atom Transfer Radical Polymerization

Abstract

The preparation of poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) grafted poly (styrene sulfonic acid) (PVDF-HFP-g-PSSA) copolymer as proton-conducting electrolytes by atom transfer radical polymerization of styrene sulfonic acid at the secondary halogenated sites of PVDF-HFP was demonstrated. The structure of the PVDF-HFP-g-PSSA copolymers was verified by Fourier transform infrared spectra, proton nuclear magnetic resonance spectra and X-ray photoelectron spectroscopy. The PVDF-HFP-g-PSSA copolymer membranes showed ion exchange capacity values ranging from 0.045 to 0.272 mEq g^-1, the water uptake varied from 13.7 to 26.8 wt.% and the proton conductivities varying from 1.85 2 10^-4 to 9.8 2 10^-4 S cm^-1, all of which could be modulated by control of the polymerization time. All the membranes exhibited decomposition temperature up to around 350 °C as revealed by thermogravimetric analysis. The incorporation of poly(styrene sulfonic acid) into PVDF-HFP chains resulted in melting at higher temperatures. The scanning electron microscopy observation indicated that the density of the ionic pathways increased with ionic content, which explained why the ionic conductivity rose to relatively high values as polymerization time increasing.

Keywords

Polymer electrolyte membrane atom transfer radical polymerization (ATRP)poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP)proton conductivity

Get full access to this article

View all access options for this article.

References

Hickner, A. , Ghassemi, H. , Kim, Y.S. , Einsla, B.R. and McGrath J.E. (2004). Alternative Polymer Systems for Proton Exchange Membranes (PEMs), Chem. Rev., 104: 4587-4612.

Mehta, V. and Cooper, J.S. (2003). Review and Analysis of PEM Fuel Cell Design and Manufacturing, J. Power Source, 114: 32-53.

Meier-Haack, J. , Taeger, A. , Vogel, C. , Schlenstedt, K. , Lenk, W. and Lehmann, D. (2005). Membranes from Sulfonated Block Copolymers for Use in Fuel Cells, Separat. Purificat. Technol., 41: 207-220.

Rikukawa, M. and Sanui, K. (2000). Proton-conducting Polymer Electrolyte Membranes Based on Hydrocarbon Polymers, Prog. Polym. Sci., 25: 1463-1502.

Inzelt, G. , Pineri, M. , Schultze, J.W. and Vorotyntsev, M.A. (2000). Electron and Proton Conducting Polymers: Recent Developments and Prospects, Electrochim Acta , 45: 2403-2421.

Li, Q.F. , He, R.H. , Jensen, J.O. and Bjerrum, N.J. (2003). Approaches and Recent Development of Polymer Electrolyte Membranes for Fuel Cells Operating above 100 Degrees C, Chem. Mater., 15: 4896-4915.

Zhong, S.L. , Fu, T.Z. , Dou, Z.Y. , Zhao, C.J. and Na, H. (2006). Preparation and Evaluation of a Proton Exchange Membrane based on Crosslinkable Sulfonated Poly(ether ether ketone)s, J. Power Source, 162: 51-57.

Chen, Y.L. , Meng, Y.Z. , Wang, S.J. , Tian, S.H. , Chen, Y. and Hay, A.S. (2006). Sulfonated Poly(fluorenyl ether ketone) Membrane Prepared via Direct Polymerization for PEM Fuel Cell Application, J. Membr. Sci., 280: 433-441.

Liu, B.J. , Kim, D.S. , Murphy, J. , Robertson, G.P. , Guiver, M.D. , Mikhailenko, S. , Kaliaguine, S. , Sun, Y.M. , Liu, Y.L. and Lai, J.Y. (2006). Fluorenyl-containing Sulfonated poly(aryl ether ether ketone ketone)s (SPFEEKK) for Fuel Cell Applications , J. Membr. Sci., 280: 54-64.

10.

Chen, Y.L. , Meng, Y.Z. and Hay, A.S. (2005). Direct Synthesis of Sulfonated Poly(phthalazinone ether) for Proton Exchange Membrane Via N-C Coupling Reaction, Polymer, 46: 11125-11132.

11.

Ding, F.C. , Wang, S.J. , Xiao, M. and Meng, Y.Z. (2007). Cross-linked Sulfonated Poly(phathalazinone ether ketone)s for PEM Fuel Cell Application as Proton-Exchange Membrane, J. Power Source, 164: 488- 495.

12.

Fu, Y. and Manthiram, A. (2006). Synthesis and Characterization of Sulfonated Polysulfone Membranes for Direct Methanol Fuel Cells, J. Power Source, 157: 222-225.

13.

Dai, H. , Guan, R. , Li, C.H. and Liu, J.H. (2007). Development and Characterization of Sulfonated Poly(ether sulfone) for Proton Exchange Membrane Materials, Solid State Ionics, 178: 339-345.

14.

Li, Y.X. , Wang, F. , Yang, J. , Liu, D. , Roy, A. , Case, S. , Lesko, J. and McGrath, J.E. (2006). Synthesis and Characterization of Controlled Molecular Weight Disulfonated Poly(arylene ether sulfone) Copolymers and their Applications to Proton Exchange Membranes, Polymer , 47: 4210-4217.

15.

Karlsson, L.E. and Jannasch, P. (2004). Polysulfone Ionomers for Proton-conducting Fuel Cell Membranes: Sulfoalkylated Polysulfone, J. Membr. Sci., 230: 61-70.

16.

Fang, J. , Shen, P.K. and Liu, Q.L. (2007). Low Methanol Permeable Sulfonated Poly(phthalazinone ether sulfone)membranes for DMFCs, J. Membr. Sci., 293: 94-99.

17.

Go, S. , He, G.H. , Wu, X.M. , Li, C.N. , Liu, H.J. , Lin, C. and Li, X.C. (2006). Synthesis and characteristics of sulfonated poly(phthalazinone ether sulfone ketone) (SPPESK) for direct methanol fuel cell (DMFC), J. Membr. Sci., 281: 121-129.

18.

Jang, W. , Kim, D. , Choi, S. , Shul, Y.G. and Han, H. (2006). Synthesis and Characterization of Sulfonated Polyimides Containing Aliphatic Linkages in the Main Chain, Polym. Int. , 55: 1236-1242.

19.

Rodgers, M. , Yang Y. S. and Holdcroft , S. (2006). A Study of Linear Versus Angled Rigid Rod Polymers for Proton-Conducting Membranes using Sulfonated Polyimides, European Polym. J., 42: 1075-1085.

20.

Ye, X.H. , Bai, H. and Ho, W.S.W. (2006). Synthesis and Characterization of New Sulfonated Polyimides as Proton-exchange Membranes for Fuel Cells, J. Membr. Sci., 279: 570-577.

21.

Hu, Z.X. , Yin, Y. , Kita, H. , Okamoto, K.I. , Suto, Y. , Wang, H.G. and Kawasato, H. (2007). Synthesis and Properties of Novel Sulfonated Polyimides Bearing Sulfophenyl Pendant Groups for Polymer Electrolyte Fuel Cell Application, Polymer, 48: 1962-1971.

22.

Li, Y.H. , Jin, R.Z. , Cui, Z.M. , Wang, Z. , Xing, W. , Qiu, X.P. , Ji, X.L. and Gao, L.X. (2007). Synthesis and Characterization of Novel Sulfonated Polyimides from 1,4-bis(4-aminophenoxy)-naphthyl-2,7-disulfonic acid, Polymer, 48: 2280-2287.

23.

Chen, S.W. , Yin, Y. , Tanaka, K. , Kita, H. and Okamoto, K. (2006). Synthesis and Properties of Novel Side-Chain-Sulfonated Polyimides from bis[4-(4-aminophenoxy) -2-(3-sulfobenzoyl)]phenyl Sulfone , Polymer, 47: 2660-2669.

24.

Li, N.W. , Cui, Z.M. , Zhang, S.B. and Xing, W. (2007). Synthesis and Characterization of Rigid-rod Sulfonated Polyimides bearing Sulfobenzoyl Side Groups as Proton Exchange Membranes, J. Membr. Sci., 295: 148-158.

25.

Daletou, M.K. , Gourdoupi, N. and Kallitsis, J.K. (2005). Proton Conducting Membranes Based on Blends of PBI with Aromatic Polyethers Containing Pyridine Units , J. Membr. Sci., 252: 115-122.

26.

Wycisk, R. , Chisholm, J. , Lee, J. , Lin, J. and Pintauro, P.N. (2006). Direct Methanol Fuel Cell Membranes from Nafion-polybenzimidazole Blends, J. Power Source, 163: 9-17.

27.

Qing, S.B. , Huang, W. and Yan, D.Y. (2005). Synthesis and Characterization of Thermally Stable Sulfonated Polybenzimidazoles, Eur. Polym. J., 41: 1589-1595.

28.

Xu, H.J. , Chen, K.C. , Guo, X.X. , Fang, J.H. and Yin, J. (2007). Synthesis of Hyperbranched Polybenzimidazoles and their Membrane Formation, J. Membr. Sci., 288: 255-260.

29.

Cui, Z.M. , Liu, C.P. , Lu, T.H. and Xing, W. (2007). Polyelectrolyte Complexes of Chitosan and Phosphotungstic Acid as Proton-conducting Membranes for Direct Methanol Fuel Cells, J. Power Source, 167: 94-99.

30.

Chuang, S.W. , Hsu, S.L.C. and Hsu , C.L. (2007). Synthesis and Properties of Fluorine-containing Polybenzimidazole/montmorillonite Nanocomposite Membranes for Direct Methanol Fuel Cell Applications, J. Power Source, 168: 172-177.

31.

Sauk, J. , Byun, J. and Kim, H. (2005). Composite Nafion/polyphenylene oxide (PPO) Membranes with Phosphomolybdic Acid (PMA) for Direct Methanol Fuel Cells, J. Power Source, 143: 136-141.

32.

Thangamuthu, R. and Lin, C.W. (2005). DBSA-doped PEG/SiO2 Proton-conducting Hybrid Membranes for Low-Temperature Fuel Cell Applications , Solid State Ionics, 176: 531-538.

33.

Mukoma, P. , Jooste, B.R. and Vosloo, H.C.M. (2004). Synthesis and Characterization of Cross-linked Chitosan Membranes for Application as Alternative Proton Exchange Membrane Materials in Fuel Cells, J. Power Source, 136: 16-23.

34.

Wu, S.Q. , Qiu, Z.M. , Zhang, S.B. , Yang, X.R. , Yang, F. and Li, Z.Y. (2006). The Direct Synthesis of Wholly Aromatic Poly(p-phenylene)s Bearing Sulfobenzoyl Side Groups as Proton Exchange Membranes, Polymer, 47: 6993-7000.

35.

Gomes, D. , Roeder, J. , Ponce, ML and Nunes, S.P. (2007). Characterization of Partially Sulfonated Polyoxadiazoles and Oxadiazole-Triazole Copolymers, J. Membr. Sci., 295: 121-129.

36.

Shang, X.Y. , Shu, D. , Wang, S.J. , Xiao M. and Meng, Y.Z. (2007). Fluorene-containing Sulfonated Poly(arylene ether 1,3,4-oxadiazole) as Proton-exchange Membrane for PEM Fuel Cell Application, J. Membr. Sci., 291: 140-147.

37.

Tsang, E.M.W. , Zhang, Z. , Shi, Z. , Soboleva, T. and Holdcroft, S. (2007). Considerations of Macromolecular Structure in the Design of Proton Conducting Polymer Membranes: Graft versus Diblock Polyelectrolytes, J. Am. Chem. Soc., 129: 15106-15107.

38.

Siu, A. , Pivovar, B. , Horsfall, J. , Lovell, K.V. and Holdcroft , S. (2006). Dependence of Methanol Permeability on the Nature of Water and the Morphology of Graft Copolymer Proton Exchange Membranes, J. Polym. Sci. Part B: Polym. Phys., 44: 2240-2252.

39.

Holmberg, S. , Holmlund, P. , Nicolas, R. , Wilen, C.E. , Kallio, T. and Sundholm, G. (2004). Versatile Synthetic Route to Tailor-Made Proton Exchange Membranes for Fuel Cell Applications by Combination of Radiation Chemistry of Polymers with Nitroxide-Mediated Living Free Radical Graft Polymerization, Macromolecules, 37: 9909-9915.

40.

Holmberg, S. , Holmlund, P. , Wilen, C.E. , Kallio, T. , Sundholm, G. and Sundholm, F. (2002). Synthesis of Proton-conducting Membranes by the Utilization of Preirradiation Grafting and Atom Transfer Radical Polymerization Techniques, J. Polym. Sci. Part A: Polym. Chem., 40: 591-600.

41.

Shen, Y. , Qiu, X.P. , Shen, J. , Xi, J.Y. and Zhu, W.T. (2006). PVDF-g-PSSA and Al2O3 Composite Proton Exchange Membranes, J. Power Sources, 161: 54-60.

42.

Shen, M. , Roy, S. , Kuhlmann, J.W. , Scott, K. , Lovell, K. and Horsfall, J.A. (2005). Grafted Polymer Electrolyte Membrane for Direct Methanol Fuel Cells, J. Membr. Sci., 251: 121-130.

43.

Nasef, M.M. , Zubir, N.A. , Ismail, A.F. , Khayet, M. , Dahlan, K.Z.M. and Saidi, H. (2006). PSSA Pore-filled PVDF Membranes by Simultaneous Electron Beam Irradiation: Preparation and Transport Characteristics of Protons and Methanol, J. Membr. Sci., 268: 96-108.

44.

Liu, D.M. , Chen, Y.W. , Zhang, N. and He, X.H. (2006). Controlled Grafting of Polymer Brushes on Poly(Vinylidene Fluoride) Films by Surface-Initiated Atom Transfer Radical Polymerization, J. Appl. Polym. Sci. , 101: 3704-3712.

45.

Hester, J.F. , Banerjee, P. , Won, Y.Y. , Akthakul, A. , Acar, M.H. and Mayes, A.M. (2002). ATRP of Amphiphilic Graft Copolymers Based on PVDF and Their Use as Membrane Additives, Macromolecules, 35: 7652-7661.

46.

Beers, K.L. , Gaynor, S.G. and Matyjaszewski, K. (1998). The Synthesis of Densely Grafted Copolymers by Atom Transfer Radical Polymerization, Macromolecules, 31: 9413-9415.

47.

Gu, L. , Zhu, S. and Hrymak, A.N. (1998). Modeling Molecular Weight Distribution of Comb-Branched Graft Copolymers J. Polym. Sci. Part B: Polym. Phys., 36: 705-714.

48.

Paik, H.J. , Gaynor, S.G. and Matyjaszewski, K. (1998). Synthesis and Characterization of Graft Copolymers of Poly(Vinyl Chloride) with Styrene and (Meth)Acrylates by Atom Transfer Radical Polymerization, Macromol. Rapid. Commun, 19: 47-52.

49.

Chen, Y.W. , Liu, D.M. , Deng, Q.L. , He, X.H. and Wang, X.F. (2006). Atom Transfer Radical Polymerization Directly from Poly(vinylidene fluoride):Surface and Antifouling Properties, J. Polym. Sci. Part A: Polym. Chem., 44: 3834-3443.

50.

Kim, Y.W. , Lee, D.K. , Lee, K.J. and Kim, J.H. (2008). Single-step Synthesis Of Proton Conducting Poly(vinylidene fluoride) (PVDF) Graft Copolymer Electrolytes, Eur. Polym. J., 44: 932-939.

51.

Matyjaszewski, K. , Miller, P.J. , Shukla, N. , Immaraporn, B. , Gelman, A. , Luokala, B.B. , Siclovan, T.M. , Kickelbick, G. , Vallant, T. , Hoffmann, H. and Pakula, T. (1999). Polymers at Interfaces: Using Atom Transfer Radical Polymerization in the Controlled Growth Of Homopolymers and Block Copolymers from Silicon Surfaces in the Absence of Untethered Sacrificial Initiator, Macromolecules, 32: 8716-8724.

52.

Kim, J.H. , Min, B.R. , Kim, C.K. , Won, J. and. Kang, Y.S. (2002). New Insights into the Coordination Mode of Silver Ions Dissolved in Poly(2-Ethyl-2-Oxazoline) and its Relation to Facilitated Olefin Transport, Macromolecules , 35: 5250-5255.

53.

Qiu, Z.M. , Wu, S.Q. , Li Z. , Zhang, S.B. , Xing W. and Liu, C.P. (2006). Sulfonated Poly(arylene-co-naphthalimide)s Synthesized by Copolymerization of Primarily Sulfonated Monomer and Fluorinated Naphthalimide Dichlorides as Novel Polymers for Proton Exchange Membranes , Macromolecules, 39: 6425-6432.