Electrochemistry of conductive polymers XXIV.: Polypyrrole films grown at electrodes modified with β-cyclodextrin molecular templates

Electrochemical properties of polypyrrole films grown in 0.10 M LiClO4 acetonitrile solutions (+ 2% H2O) at gold electrodes modified with thiolated beta -cyclodextrin (beta -CD) self assembled monolayers (SAMs) have been investigated using cyclic voltammetry, electrochemical impedance spectroscopic measurements, and scanning electron microscopy. The polymerization reaction rate displayed a 0.68th order with respect to the pyrrole concentration and a 0.41th order with respect to the amount of polypyrrole. The initial growth rate of polypyrrole at the SAM-modified electrode was slower than that at bare gold electrodes. The polypyrrole films grown galvanostatically at the SAM-modified electrodes showed the spectroscopic characteristics of nanosized polymer fibers, as well as lower distributed capacitance, than those grown at bare gold electrodes under otherwise the same experimental conditions. Scanning electron microscopic pictures reveal that the thiolated beta -CDs act as molecular templates to restrict the growth sites within the beta -CD cavities. (C) 2000 The Electrochemical Society. S0013-4651(00)02-098-X. All rights reserved.