Solid state electron-hopping transport and frozen concentration gradients in a mixed valent viologen-tetraethylene oxide copolymer
- Univ. of North Carolina, Chapel Hill, NC (United States)
This paper describes electrochemistry and electron-hopping dynamics for a novel viologen-based redox polymer (poly-V{sup 2+}) formed from the copolymerization of tetraethylene glycol di-p-tosylate and 4,4{prime}-bipyridine. Current-potential responses and electron-hopping (i.e., self-exchange) rates have been measured for mixed valent films of poly-V{sup 2+} on interdigitated array electrodes contacted by tetrahydrofuran/acetonitrile/tetrabutylammonium perchlorate electrolyte solution and as dry mixed valent films in vacuum or dry nitrogen. Electron transfer rates vary with the mixed valency composition of poly-V{sup 2+/+} films (judging film composition from the electrolysis potential with the Nernst equation) according to bimolecular reaction theory for solvent-wetted but less well for dry films. Current-potential characteristics are also reported for mixed valent films that contain concentration gradients of the poly-V{sup 2+} and poly-V{sup +} redox states, which we attempt to freeze into place by drying the film under a gradient-generating potential bias so as to immobilize the film`s counterions. Current transients at room and reduced (-30{degree}C) temperature show that the room-temperature responses of films containing concentration gradients are sensitive to small changes in poly-V{sup 2+/+} oxidation state at the electrode/polymer interfaces. 24 refs., 9 figs., 1 tab.
- OSTI ID:
- 501904
- Journal Information:
- Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical, Journal Name: Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical Journal Issue: 9 Vol. 101; ISSN 1089-5647; ISSN JPCBFK
- Country of Publication:
- United States
- Language:
- English
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