Polypyrrole polystyrene sulfonate

Although all solid state reference electrodes based on conducting polymers have been tested, they are still in the testing phase. The most promising systems appear to be bilayers with different ion-exchanger properties such as glassy carbon/polypyrrole in conjunction with a polypyrrole(polystyrene sulfonate) layer 64,65). 

Osaka, T., Momma, T., and Nishimura, K., Electroactivity change of electropoiymer-ized polypyrrole/polystyrene-sulfonate composite film in some oiganic electrolytes, Chem. Utt., 1787-1788 (1992). 

From an analysis of data for polypyrrole, Albery and Mount concluded that the high-frequency semicircle was indeed due to the electron-transfer resistance.203 We have confirmed this using a polystyrene sulfonate-doped polypyrrole with known ion and electron-transport resistances.145 The charge-transfer resistance was found to decrease exponentially with increasing potential, in parallel with the decreasing electronic resistance. The slope of 60 mV/decade indicates a Nemstian response at low doping levels. 

If the dopant anion (A ) is small and mobile (eg. Cl ) and the polymer has a high surface area to volume ratio, then upon reduction the anion will be efficiently ejected from the polymer. However, extensive studies with polypyrroles have shown [4] that if the dopant is large and immobile (eg. if A" is a polyelectrolyte such as polystyrene sulfonate) then an electrically induced cation exchange process occurs, according to Eqn. 3,... 

It was mentioned that the properties of the polymer film depend on the type of anion. In Figure 11.20, another RC versus potential diagram is shown for a polypyrrole film prepared by anodic oxidation in a polystyrene-sulfonate electrolyte. The large ion cannot... 

Figure 11.20 High frequency part of capacitance and resistance of a polypyrrole film as function of the potential. The film was prepared by anodic oxidation in a polystyrene-sulfonate electrolyte. Additionally, the cyclic voltammogram is shown, whereby the film becomes electron conducting at more positive potentials (E > -0.5 V) and ion conducting at negative potentials (E < —0.8 V).

Some applications of polypyrrole, such as drug delivery devices, require specific ion transport. Control of the ion transport process requires determination of the identity of the mobile ion, which is complicate by the fact that there are several ions present in the system. Moreover, Shimidzu and co-woiicers [138,139] demonstrated that ion transport in polypyrrole can be modified by the use of polymeric anions as dopants. Miller and Zhou [140] proved that the electrochemical switching of polypyrrole could achieve controlled release of small anions (such as CIO4), while the incorporation of an immobile polyanion (such as polystyrene sulfonate) resulted in cation transport. The polyanions become trapped within the polypyrrole matrix due to their large size and, perhaps more important, their entanglement with the polypyrrole chains. This increases the stability and mechanical strength of polypyrrole and improves electrical conductivity and electroactivity [141,142]. Therefore it has been of significant interest in the polymerization of pyrrole in polyanion electrolyte solutions [143,144]. 

Some measurements of this property have been made in a range of electrically conducting polymers. These include epoxy resin/polyaniline-dodecylbenzene sulfonic acid blends [38], polystyrene-black polyphenylene oxide copolymers [38], semiconductor-based polypyrroles [33], titanocene polyesters [40], boron-containing polyvinyl alcohol [41], copper-filled epoxy resin [42], polyethylidene dioxy thiophene-polystyrene sulfonate, polyvinyl chloride, polyethylene oxide [43], polycarbonate/acrylonitrile-butadiene-styrene composites [44], polyethylene oxide complexes with sodium lanthanum tetra-fluoride [45], chlorine-substituted polyaniline [46], polyvinyl pyrolidine-polyvinyl alcohol coupled with potassium bromate tetrafluoromethane sulfonamide [47], doped polystyrene block polyethylene [38, 39], polypyrrole [48], polyaniline-polyamide composites [49], and polydimethyl siloxane-polypyrrole composites [50]. 

Electrical properties have been reported on numerous carbon fiber-reinforced polymers, including carbon nanoflber-modified thermotropic liquid crystalline polymers [53], low-density polyethylene [54], ethylene vinyl acetate [55], wire coating varnishes [56], polydimethyl siloxane polypyrrole composites [50], polyacrylonitrile [59], polycarbonate [58], polyacrylonitrile-polycarbonate composites [58], modified chrome polymers [59], lithium trifluoromethane sulfonamide-doped polystyrene-block copolymer [60], boron-containing polyvinyl alcohols [71], lanthanum tetrafluoride complexed ethylene oxide [151, 72, 73], polycarbonate-acrylonitrile diene [44], polyethylene deoxythiophe-nel, blends of polystyrene sulfonate, polyvinyl chloride and polyethylene oxide [43], poly-pyrrole [61], polypyrrole-polypropylene-montmorillonite composites [62], polydimethyl siloxane-polypyrrole composites [63], polyaniline [46], epoxy resin-polyaniline dodecyl benzene sulfonic acid blends [64], and polyaniline-polyamide 6 composites [49]. 

Intrinsically conducting polymers (ICPs) are organic conductive materials based on poly-anUine (PANI), poly(3,4-ethylenedioxithiophene)polystyrene sulfonate (PEDOT PSS), or polypyrrole (PPy) (Ding et al., 2010 Bocchini et al., 2013). 

Py pyrrole, MPy 1-methylpyrrole, PPy polypyrrole, PMPy poly(l-methylpyrrole), EDOT 3,4-ethylenedioxytiophene, PEDOT poly(3,4-ethylenedioxytiophene), MT 3-methylthiophene, PMT poly(3-methylthiopliene), NaPSS sodium polystyrene sulfonate, NaDBS sodium dodecylbenzenesulfonate, NaPTS sodium para-toluene sulfonate, BSA benzenesulfonic acid, SSA 2-hydroxy-5-sulfobenzoic acid, MES 2-(Af-morpholino) ethanesulfonic acid, MOPS 3-(Al-morpholino) propanesulfonic acid, PIPES piperazine-l,4-bis(2-ethanesulfonic) acid, MeCN acetonitrile, DCE 1,2-dichloroetane, BU4NPF6 tetrabutylammonium hexafluor-ophosphate, BTPPA-CIO4 bis(triphenylphosphoranylidene)ammonium perchlorate, BTPPA-TFPB bis(triphenylphosphoranylidene)ammonium tetrakis[3,5-bis (trifluoromethyl)phenyl]borate, TPenA tetraphenylammonium... 

Polymeric cathodes have been studied as cathodes in molten salt systems, mainly by Koura and Osteryoung specifically polypyrrole [161-163], polythiophene [164], polyfluorene [165,166], polyanUine [167-172] and polyanUine polystyrene sulfonate [173] were evaluated. In many cases, the cathodes have been synthesized in the ionic liquids as weU. These cathodes can be used with several anodes, even aluminum. Such systems have low to moderate specific... 

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