S-Space College of Engineering/Engineering Practice School (공과대학/대학원) Dept. of Chemical and Biological Engineering (화학생물공학부) Journal Papers (저널논문_화학생물공학부)
Luminescent and Redox Probes of Structure and Dynamics in Quaternized Poly( 4-vinylpyridine) Films on Electrodes
- Oh, Seung-Mo; Faulkner, Larry R.
- Issue Date
- American Chemical Society
- J. Am. Chem. Soc. 1989, 111, 5613
- The properties of partially quaternized poly(4-vinylpyridine) films have been studied by coordinatively attaching
luminescent and redox probes to free pyridine units within the polymer. Samples were examined as thin films spin coated
onto glass or electrodes. The luminescent moiety was Re(CO),(phen) (phen = 1 ,lo-phenanthroline). It showed properties
that depended strongly on the identity of the anion in the supporting electrolyte adjacent to the film. The emission maximum
shifted to the red, and the quantum yield decreased in the order dry film > 0.1 M NaC104 > 0.1 M potassium p-toluenesulfonate
> 0.1 M KNO,. The isotope effect caused by changing the solvent from H20 to D20 fell in the reverse order. The results
show that the anion has a large impact on film structure. In nitrate the films are strongly hydrated, but in perchlorate they
are dry and compact. The redox moiety was Ru(bpy),Cl2'/'+. The activation energies for electron diffusion in the network
of redox centers were assessed by temperature-resolved chronocoulometry. The activation energies were independent of the
concentration of redox centers in the film but were ordered according to electrolyte as given above. They were roughly linearly
dependent on the degree of chemical cross-linking. The permeabilities of the films to redox-active ions in solution were larger
than the electron diffusion coefficients by an order of magnitude but were strongly dependent on the anion of the supporting
electrolyte, inversely in the order given above. The results suggest that electron diffusion is controlled by segmental motions
within the polymer and that the anion dependence is a structural effect.
- 0002-7863 (print)
- Files in This Item: There are no files associated with this item.