KIMBLE KONTES - ACS Publications - American Chemical Society

May 31, 2012 - KIMBLE KONTES. Anal. Chem. , 1992, 64 (7), pp 438A–438A. DOI: 10.1021/ac00031a722. Publication Date: April 1992. ACS Legacy Archive...
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age of CO B is comparable to that of CO L and increases at negative potentials (33). Recent in situ scanning tunneling microscopy measurements on CO adsorbed at R h ( l l l ) (34) appear to be in agreement with the composition of the adsorbed CO layer predetermined by IR spectroscopy (33). When the Rh electrode is partially covered with Cu atoms (9 C u ~ 0.2) the CO B species disappear almost entirely, whereas the CO L adsorption remains unaffected. One possible explanation for this phenomenon is that the presence of the Cu atoms leads to a decrease in the number of free neighboring Rh sites necessary for the CO species to adopt a bridge configuration. Access to this type of molecular-specific information would have been difficult to obtain by employing only conventional electrochemical measurements.

Conducting polymer thin films. Thin films of electronically conductive polymers such as polypyrrole, polythiophene, and polyaniline are being considered for diverse applications ranging from controlled drug release and chemical sensors to electrochromic displays and s m a r t windows (35). Most of these applications depend critically on the ability of the polymer to switch from an insulating (reduced) form to an electronically conductive (oxidized) form. The dynamics of this process, however, depend critically on the ionic fluxes that accompany the polymer redox process, and both anion and

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438 A · ANALYTICAL CHEMISTRY, VOL. 64, NO. 7, APRIL 1, 1992

Figure 10. Scheme for in situ luminescence monitoring of ion transport during redox electrochemistry of a polypyrrole-modified electrode. Strategies for monitoring (a) anion (A~) and (b) cation (C*) fluxes. (Adapted from Reference 36.)