| Abstract
| - A combined scanning electrochemical-atomic force microscope (SECM-AFM) has been used to probe the diffusional transport of target electroactive solutes in isolatednanopores of a track-etched membrane. A polycarbonatemembrane (100-nm-diam pore size) hydrated with anelectrolyte solution, containing a redox-active probe molecule, such as IrCl63- or Fe(phen)32+, functions as themodel membrane system. The use of a mobile Pt-coatedAFM probe enables individual solution-filled pores to betopographically identified. Analysis of the correspondingcurrent images for the diffusion-limited oxidation of theredox mediator indicates that solution is largely confinedto pores in the membrane. Moreover, the tip collectorcurrent response provides information on diffusion of themediator through the pore. Force−distance tip approachand retract measurements allow the radius of contactbetween the electrochemical-AFM tip and solution confined within a pore at the point of pull-off to be estimated.
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