engleski

The influence of frequency on fractal structuring of adsorbed layers at the mercury/electrolyte solution interface

The adsorption of organic molecules often results in monolayer with fractal structure. The fractal dimension of a layer reflects its structure and conformation of adsorbed molecules as well as dynamics of structural changes and possible phase changes during the adsorption process. In electrochemical measurements fractal dimension is determined by the method of scaling electrode size. However, (in e.g. ac voltammetry) such measurements are usually conducted at single frequency. To extend the method to the impedance spectroscopy and make it available for broader applications it is necessary to investigate the possible dependence of fractal dimension estimate on applied frequency. Here, we report and discuss the results of application of impedance spectroscopy in estimate of fractal dimension of adsorbed layers. The investigation included two organic molecules ; nonionic surfactant Triton-X-100 and tert-Butanol. All measurements were performed at thermodynamic equilibrium in 0.5 M NaCl electrolyte solution employing broad frequency spectrum. The results of the investigation confirm the applicability of the scaling electrode method for determination of fractal dimension in the impedance spectroscopy of adsorbed organic layers.

adsorption; monolayer; fractal dimensions; impedance spectroscopy

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