IONIC SURFACTANTS AS MOLECULAR SPACERS AT GRAPHITE-ELECTRODES

A surface model for rough pyrolytic graphite (RPG) and glassy carbon (GC) electrodes has been developed in ionic surfactant media. Ionic surfactant aggregates enable the control and optimization of response of these graphite electrodes. The feasibility of forming surfactant aggregates directly from solution is demonstrated. The results indicate head-on surfactant-surface interactions and formation of hemimicelles at the surface. Structural differences between RPG and GC result in differences in aggregation and consequently different effects of surfactants on probe response. Therefore, the nature of the probe along with the surface and surfactant structure must be considered for optimization of response. Furthermore, in surfactant solutions improvements in sensitivity of inactive GC and reproducibility of active RPG are demonstrated.