Scanning Electrochemical Microscopy SECM Investigations of ECPs

4 Scanning Electrochemical Microscopy (SECM) Investigations of ECPs 

Scanning electrochemical microscopy (SECM) is a scanning probe technique in which the probe is a disk ultramicroelectrode (typical radius in the 5 to 25 pm range) that scans the surface of the investigated sample facing it [157]. SECM measurements are carried out in 

The feedback mode of SECM was used to map the conductivity of a fluoroborate-doped polypyrrole film and to evaluate its potential dependence [158]. An ultramicroelectrode (UME), 12.5 pm in diameter, was used to detect the redox mediator more or less concentrated in the UME vicinity, depending on the ability of the polymer film to regenerate it, thus providing the potential region where the polypyrrole film is electronically conducting. 

SECM was also used to evaluate the conductivity changes of polybithiophene microstructures deposited by a laser-assisted microstructuring deposition technique as a function of their doping level, controlled by fixing the potential value at the polymer sample [ 163]. In order to achieve this purpose, the feedback mode of SECM was used in an electrolytic solution containing [IrfCNjg].  

From SECM studies of the electrochemical doping and undoping processes of poly-(didodecyl-terthiophene), the electron transfer between the polymer and a redox mediator in solution was investigated as a function of the doping state of the polymer [164], The electron transfer was found to occur at the polymer-electrolytic-solution interface and not inside the polymer film. The investigated polymer films are not permeable to redox species when placed in the neutral state and therefore behave as completely passivating films. 

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