Enhanced electrical conductivity of polyindole prepared by electrochemical polymerization of indole in ionic liquids

Abstract

The in situ electrical conductivity (resistance) of electrochemically prepared polyindole (PIn) in ionic liquids was found to be strongly dependent on the nature of the solvents, size of ionic liquid counter ions and preparation technique. Accordingly, the conductivity can be enhanced by about one order of magnitude when using a 1-butyl-3-methylimidazolium tetrafluoroborate [BMIm] [BF 4 -] or 1-butyl-3-methylimidazolium hexafluorophosphate [BMIm] [PF 6 2 ] in comparison to acetonitrile (ACN). Moreover, the growth of polyindole in ionic liquid on gold electrode surface is faster than growth of polymer in acetonitrile. Additionally, a significant enhancement of the conductivity by using ionic liquids during the polymerization could be achieved. V C 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40094.

Critical analysis of polyindole and its composites in supercapacitor application

“…The advantages of these advance synthetic techniques involve excellent reduction-oxidation activity, and thermal and physical stability of the polymer synthetized and sluggish rate of degradation [17,25]. As observed, the electrochemically synthesized π-conjugated polymers in ionic solution do show improved lifecycles and rapid cycle switching speeds without considerable material loss [27]. Cyclic voltammetry (CV, 1.2 V) technique was effectively used for polymerization of indole on the surface of Pt (Platinum) in solution containing 0.1 M NaClO 4 , the green-coloured precipitate signifies the generated polymer [28].…”

“…The conductance of PIN among various CP is observed to be less (close to 0.1 S cm −1 ) owing to their instability, degradation, chain unevenness, etc. However, the properties of dopant (its size and nature) and nature of electrolyte-molecular solvent system can have a discernible impact on the conductance of the subsequent polymer [27]. In addition, in the case of electrochemical storage, the scan rate effects of the current response, with lower rates of scanning the thick diffusion layers, are formed which are responsible for reduced current response while vice versa for high scan rate [34,37].…”

“…CAN[27]. However, the conductivity of PIN in CAN was higher thanPIN electropolymerized in [BMIm] [BF4 − ] and [BMIm] [PF 6 − ] by an order of 0.8 and 0.4, respectively.…”

Effect of supporting electrolyte on capacitance and morphology of electrodeposited poly(3,4-propylenedioxythiophene) derivatives bearing reactive functional groups

“…This finding is consistent with the previous report that the growth rates of polyindole film in the ionic liquid BMImBF 4 /ACN are faster than that of polyindole growth in BMImPF 6 /ACN dependent on the nature of the ionic liquid and size of dopant ions, where the size of PF 6 − dopant ions are larger than BF 4 − . 79 The potential window selected for each electrolyte or derivative indicates a suitable polymer film growth. As reported earlier, no polymer formation attains at a lower potential, or the polymerization rate is prolonged to reach desired film thickness.…”

Synthesis and electrochemical investigation of polyindole based fiber as sensor electrode by EIS method

“…PIN is one of the many electroactive polymers, which can be obtained by anodic oxidation of indole in various electrolytes [15]. Because of the structural resemblances of indole to pyrrole most of the structure and polymerization mechanism for PIN have been taken from polypyrrole studies [16][17][18][19][20][21]. Although, PIN films have mainly been synthesized through electrochemical oxidation [22], chemical oxidation of indole monomer by the direct chemical oxidation in the presence of FeCl 3 , CuCl 2 or (NH 4 ) 2 S 2 O 8 [23,24] has also been reported.…”