Electropolymerization of a Cation-permeable Layer Using 1-pyrrolyl-10-decanephosphonic Acid

摘要

The electrochemical deposition of a novel N-substituted polypyrrole, 1-pyrrolyl-10-decanephosphonic acid, is presented. The properties of the film are found to be highly dependent on the potential range used during deposition. Self-terminated growth of a thin, non-conducting layer is observed when using anodic switching potentials of at least 1.8V versus Ag/AgI. At anodic potentials between 1.5V and 1.8V, growth of a conducting polymer layer is possible, although, continued growth results in increased resistance of the film and gradual transition to a nonconducting state. A long-lived intermediate formed during the oxidation of the monomer is observed. Reduction of this intermediate, resulting in changes in the cyclic voltammogram, occurs at c.a. 400mV. Fourier Transform Infrared Spectroscopy of the film confirms the presence of the tethered phosphonates in the film. In aqueous solution the insulating films are permeable to Ru(NH_3)_6~(2+)/Ru(NH_3)_6~(3+) but impermeable to (Fe(CN)_6)~(3-)/(Fe(CN)_6)~(4-).