Suppression of the loss of an electroactive dopant from polypyrrole by using a non-aqueous electrolyte of dopant-phobicity

Hwang, Ryeo Yun; Kim, Sung Yeol; Palmore, G. Tayhas R.; Song, Hyun‐Kon

doi:10.1016/j.jelechem.2011.03.028

Cited by 5 publications

(2 citation statements)

References 24 publications

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“…Use of a "dopant-phobic" electrolyte solution prevented the release of dopant anions from PPy, thus avoiding overoxidation [221]. A hydrophobic nature and the electronwithdrawing character of the attached carborane cage have been suggested as reasons for the resistance of polymers, starting with 3-(neutral ortho-and anionic nido-carborane cage)-substituted pyrroles against high positive electrode potentials [222][223][224].…”

Section: How To Inhibit Prevent or Meliorate Overoxidationmentioning

confidence: 99%

Overoxidation of Intrinsically Conducting Polymers

Holze

2022

Polymers

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Intrinsically conducting polymers may undergo significant changes of molecular structure and material properties when exposed to highly oxidizing conditions or very positive electrode potentials, commonly called overoxidation. The type and extent of the changes depend on the experimental conditions and chemical environment. They may proceed already at much lower rates at lower electrode potentials because some of the processes associated with overoxidation are closely related to more or less reversible redox processes employed in electrochemical energy conversion and electrochromism. These changes may be welcome for some applications of these polymers in sensors, extraction, and surface functionalization, but in many cases, the change of properties affects the performance of the material negatively, contributing to material and device degradation. This report presents published examples, experimental observations, and their interpretations in terms of both structural and of material property changes. Options to limit and suppress overoxidation are presented, and useful applications are described extensively.

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Section: How To Inhibit Prevent or Meliorate Overoxidationmentioning

confidence: 99%

Overoxidation of Intrinsically Conducting Polymers

Holze

2022

Polymers

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“…Reversible reduction and oxidation of CPs during potential cycling is at the heart of a variety of technologies including rechargeable polymer batteries, − electrochromic devices, − sensors, − actuators, − and conductive supports for electrocatalysis. − Their intrinsic electrical conductivity and other electro-chemomechanical properties have been found to be dependent on such conformational changes. ,− Redox switching of CP films involves both electron and ion transport with a concomitant change in volume. This change in volume primarily is caused by the transport of solvent associated with charge-compensating mobile ions into and out of CP films with secondary contributions from conformational changes in the polymer backbone (i.e., twisted to planar) and changes in the length of the carbon–carbon bonds. − Composite films of pPy with anionic dopants of varying size and mobility such as chloride, tosylate, indigo carmine (IC), DBSA, and ABTS have been reported in the literature. ,,,− The nature of mobile ions in the charge compensation mechanism of pPy in the pPy[D] composite can be cationic or anionic depending on the size and mobility of the dopant D. , Figure shows the changes in the structure of pPy[D] as a function of redox switching, where D – is an immobile anionic dopant. The bulky nature of the dopant restricts its motion and therefore necessitates influx and efflux of cations from the electrolyte during redox switching to compensate charge on the pPy backbone.…”

Section: Introductionmentioning

confidence: 99%

Stimuli-Responsive Macromolecular Composites: Enhanced Stress Modulation in Polypyrrole with Redox-Active Dopants

Sen

Palmore

2016

Macromolecules

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Structure and conformation of conducting polymer (CP) films have been widely investigated to understand the variation in electrical, chemical, and mechanical properties in different electrochemical environments. The pH-dependent stress response in films of polypyrrole (pPy) doped with three bulky dianionic dopants (indigo carmine (IC), anthraquinone disulfonate (AQ), and naphthalene disulfonate (NP)) were studied using the multibeam optical stress sensor (MOSS) technique. Based on combined current, stress, and mass analysis, a mechanism of mixed ion dynamics is proposed that explains the electro-chemomechanical behavior of these polymers. By changing the pH of the electrolyte from neutral to acidic, a modulation of the stress response (ΔStress) of these polymers is observed, which was found to be the largest in pPy[IC] (80% decrease) compared to related structural analogues, pPy[AQ] (33%) and pPy[NP] (30%). The decrease in stress response for pPy[IC] and pPy[AQ] is attributed to the simultaneous and opposing motion of charge compensating mobile ions induced by redox activity of the quinone moiety in both IC and AQ. A secondary contributor to stress modulation in pPy[IC] arises from the conformational flexibility of the dopant molecule (IC), which translates into macromolecular flexibility of the polymer composite. The polymeric host (pPy) serves to amplify and propagate the conformation changes of IC.

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