Polyaniline composite membranes

Choi BG, Park HS, Im HS, Kim YJ, Hong WH (2008) Influence of oxidation state on physicochemical and transport properties of nafion/polyaniline composite membrane for DMFC. J Membr Sci 324 102-110... 

Figure 5.13 Change in electronic conductivity of surfaces of composite membranes composed of cation exchange membranes, NEOSEPTA CM-l, and polyaniline. After the cation exchange membrane had been immersed in an aqueous 10% aniline hydrochloride solution for 24 h, it was then immersed in a l.ON ammonium peroxodisulfate solution for various periods, washed with pure water, and completely dried.

T. Sata, Y. Ishii, K. Kawamura and K. Matsusaki, Composite membranes prepared from cation exchange membranes and polyaniline and their transport properties in electrodialysis, J. Electrochem. Soc., 1999,146, 585. 

Kinetic studies. J Appl Polytn Sci 2010, 117 (6), 3615-3622 (0 H.-J. Lee, B. Doo Chin, S.-M. Yang, O. O. Park, Surfactant effect on the stability and elec-trorheological properties of polyaniline particle suspension. J Colloid Inter/ Sci 1998, 206 (2), 424-438 (g) D. Mahanta, G. Madras, S. Radhakrishnan, S. Patil, Adsorption of sulfonated dyes by polyaniline emeraldine salt and its kinetics. J Phys Chem B 2008, 112 (33), 10153-10157 (h) N. V. Blinova, J. Stejskal, J. M. Frechet, F. Svec, Effect of reaction conditions on film morphology of polycuiibne composite membranes for gcis separation. J Polym Sci A Polym Chem 2012,50 (15), 3077-3085. 

Park et al. [102] reported a noticeable reduction of the methanol uptake in Nafion/polypyrrole composite membranes, which is accompanied by a similar decrease in the water sorption. A Nafion/polyaniline membrane containing polyanilines with different oxidation states is reported [127] to reduce around 10 % the methanol uptake, particularly the oxidized state, along with a very small reduction of the water uptake. A similar study on Nafion/polyaniline membrane reported a larger reduction (40 %) of the methanol uptake, which reached 50 % when Si02 was added to the composite membrane, without any significant effect on the water uptake [125]. 

Chen CY, Gamica-Rodriguez JI, Duke MC, Dalla Costa RF, Dicks AL, Diniz da Costa JC (2007) Naflon/polyaniline/silica composite membranes for direct methanol fuel cell application. J Power Sources 166 324-330... 

Wang CH, Chen CHC, Du HY, Chen CP, Hwang JY, Chen LC, Shih HC, Stejskal J, Chen KH (2009) Low methanol-permeable polyaniline/Nafion composite membrane for direct methanol fuel cells. J Power Sources 190 279-284... 

R.K. Nagarale, G.S. Gohil, V.K. Shahi, Sulfonated poly(ether ether ketone)/polyaniline composite proton-exchange membrane, J. Membrane Sci., 280 (2006) 389-396... 

BLI 12] Blinova N.V., Svec F., Functionalized polyaniline-based composite membranes with vastly improved performanee for separation of earbondioxide from methane , Journal of Membrane Science, vol. 423-424, pp. 514-521,2012. 

Polyaniline (PANI) nanocomposite membranes are also prepared by a sol-gel process, embedding silica in the hydrophilic clusters (Nafion) followed by its deposition by redox polymerization [51]. PANI modified the membrane structure and reduced the methanol crossover, while silica Incorporation improved the conductivity and stability. Zeolite has been incorporated as potential filler for PEMs, either by blending or by infiltration in swelled membrane, to reduce the methanol permeability and enhance the thermal stabihty [52,53]. Although the fuel cell performance of these membranes was Inferior compared with pristine Nafion membrane, incorporation of semipermeable particles is an effective method to engineer the transport properties of composite membranes. Chen et al [54] reported nanocomposite membranes by in situ hydrothermal crystallization method, with similar proton conductivity, but low methanol permeability (40% less) in comparison with Nafion membrane. These membranes showed higher OCV (3%) and power density (21%) than Nafion. 

Sol-gel-derived SPEEK-Ti02 hybrid membranes (with varied nanosized Ti02 content) showed improvement in water uptake and its retention along with reduction in methanol permeability [67]. Tripathi and Shahi [68] reported a polyaniline surface-modified SPEEK composite membranes of nanosized Si, Zr, and Ti oxides by sol-gel to achieve extremely low methanol permeability due to a synergetic effect, without any sacrifice in membrane... 

PE blends was promoted by the polypyrrole conducting phase inside the composite membranes [38]. It has also been shown that higher wettability of the polyaniline and polypyrrole coated microporous PE membranes provided better penetration of an aqueous electrolyte solution into the pores, and thus enhanced the transport of ions through the membranes [27],... 

Schwenzer, B., Kim, S., Vijayakumar, M., Yang, Z., Liu, J., Correlation of structural differences between Nafion/polyaniline and Nafion/polypyrrole composite membranes and observed transport properties. J. Membr. Sci. 2011, 372 (1-2), 11-19. 

Composites between polypyrrole and a variety of porous materials such as paper, cloth or wood have been made. Often the respective material was impregnated with an oxidant such as FeCls and subsequently contacted with pyrrole vapor or solution. For example, polypyrrole (and polyaniline) have been made in Nafion perfluorosulfonated ionomer membranes by treatment with aqueous ferric chloride and the monomers. ... 

For electrodialysis of a cation exchange membrane with a single polyaniline layer facing the cathode side, PNaCa does not decrease, which is in complete contrast to a cation exchange membrane with a polypyrrole layer. The ionic composition in the membrane during electrodialysis, ATNaCa of Eq. (5.5), has been measured (Figure 5.14)60 [the membrane was immediately removed from the cell... 

M. Deka, A. K. Nath, and A. Kumar, Effect of dedoped (insulating) polyaniline nanofibers on the ionic transport and interfacial stability of poly(vinylidene fluoride-hexafluoropropylene) based composite polymer electrolyte membranes, J. Membrane Set, ill, 188-194 (2009). 

Employing PAA was shown to improve the CDI performance as it acts as a cation exchange membrane. Another composite electrode composed of PANI (polyaniline) and single-walled CNTs showed a slight increase in CDI performance (-10%) compared to films composed of pure single-walled CNTs. This improvement in desalination was not only explained by the increase in the meso-pore volume but may also be related with the different EC properties of the PANI-CNT composite material." ... 

Pervaporation was next carried out to test the selectivity of polyaniline membranes toward acetic acid-water mixtures. Different feed ratios of acetic acid and water were pervaporated through both undoped and doped polyaniline, as shown in Fig. 33.18, where the feed water content is plotted versus the permeant water content. For comparison the vapor-liquid equilibrium curve for acetic acid-water [78] is plotted just above the line of no separation. From Fig. 33.18 it is clear that undoped polyaniline has a small preference for permeating water over acetic acid at essentially any composition. However, this small preference at an average water permeability of about 0.5 g mm/(m--h) is too low to have any utility. More interesting is fully HCl-doped polyaniline, which permeates water over acetic acid in a much more selective fashion. In fact, even with a mixture of 859f acetic acid-15% water, at least 93 wt % of the permeant was water. It should be pointed out that when undoped membranes are used in the presence of acids, they will partially dope the polyaniline, the extent depending on the pH of the acid used. However, when a... 

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