Alternating Current-Scanning Electrochemical Microscopy

AC-SECM is a specific mode of SECM, which can also be used as an alternative to hybrid SECM techniques to set a constant tip-substrate distance during SECM imaging. The use of AC-SECM as 

However, a notable exception is when the conductive substrate is unbiased it has been reported that, in such cases, provided a low AC frequency and low supporting electrolyte concentration are used, an AC-SECM feedback signal, similar to the one recorded at insulating surfaces, that is, negative feedback, is obtained [103]. In this particular case, AC-current-based constant distance amperometric SECM imaging can be implanented. 

AC-SECM has notably been used for single-cell studies. The specific advantage of AC-SECM for imaging cells is that, as mentioned earlier, no potentially toxic redox mediator has to be added to 

So far, only the use of AC current measurements as a distance regulation mechanism have been considered however, AC-SECM can also be used in the fixed height mode to image the topography 

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AC-SECM Alternating current scanning electrochemical microscopy... 

B.B. Katemann, A. Schulte, E.J. Calvo, M. Koudelka-Hep, W. Schuhmann, Localized electrochemical impedance spectroscopy with high lateral resolution by means of alternating current scanning electrochemical microscopy, Electrochem. Commun. 4 (2002) 134-138. 

Alternating current scanning electrochemical microscopy (AC-SECM) was recently used to detect precursor sites for localized corrosion on lacquered tinplates (114). AC-SECM utilizes the effect of an increasing (decreasing) solution resistance as the SECM tip approaches an insulator (conductor) for mapping domains of different conductivity/electrochemical activity on surfaces immersed in electrolytes. It was demonstrated that AC-SECM could be used to visualize microscopic cracks and holes in the coating of the lacquered tinplates. 

Katemann, B. B., Inchauspe, C. G., Castro, P. A., Schulte, A., Calvo, E. J., Schuhmann, W. Precursor sites for localised corrosion on lacquered tinplates visualised by means of alternating current scanning electrochemical microscopy. /ecfroc/jZm. Acta 2003,48, 1115-1121. 

Diakowski, R M., Ding, Z. Interrogation of living cells using alternating current scanning electrochemical microscopy (AC-SECM). PCCP 2007, 9, 5966-5974. 

Belger, S., A. Schulte, C. Hessing, M. Pohl, and W. Schuhmann, Alternating current scanning electrochemical microscopy (AC-SECM) studies on the surface of electrochemically pohshed NiTi shape memory alloys, Materialwiss Werkstofflech, 35, 2004, 276. 

Eckhard, K., T. Erichsen, M. Stratmann, and W. Schuhmann, Frequency-dependent alternating-current scanning electrochemical microscopy (4D AC-SECM) for local visualisation of corrosion sites. Chemistry—A European Journal, 14, 2008, 3968. 

K. Eckhard, H. Shill, B. MizaikofF, W. Schuhmann, C. Kranz, Alternating current (AC) impedance imaging with combined atomic force scanning electrochemical microscopy (AFM-SECM), Electrochem. Commun. 9 (2007) 1311-1315. 

Ervin, E. N., H. S. White, and L. A. Baker, Alternating current impedance imaging of membrane pores using scanning electrochemical microscopy. Anal. Chem., Vol. 77, 2005 pp. 5564-5569. 

Eckhard, K., Schuhmann, W. Alternating current techniques in scanning electrochemical microscopy (AC-SECM). Analyst 2008, 133, 1486-1497. 

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