Langmuir, Vol.18, No.24, 9447-9452, 2002
Interfacial behavior of p-hexasulfonato-calix[6]arene at glassy carbon electrodes in alkaline aqueous solution studied by voltammetric methods
The water soluble calixarene p-hexasulfonato-calix[6]arene (pSC6) was subjected to voltammetric oxidation studies in alkaline aqueous solution (pH 13) at glassy carbon (GC) working electrodes. Cyclic voltammetry revealed that the oxidation of pSC6 resulted in a narrower and more intense peak as the potential scan rate was decreased. This suggested a process whereby attachment of pSC6 to the electrode surface occurred during the time frame from initial application of potential to commencement of oxidation, in effect a potential- and/or time-controlled attachment process. Further investigations confirmed this behavior. Adsorptive voltammetry (AdV) studies at GC electrodes revealed a response attributed to the oxidation of pSC6 accumulated at the electrode surface. The intensity and behavior of this response were a function of the accumulation potential, the accumulation time, the scan rate, and the concentration of pSC6. The surface attachment process is discussed in terms of the applied potential with respect to the potential of zero charge and multilayer deposition of pSC6 on the surface.