Nonexponential relaxations in sensor arrays: forecasting strategy for electronic nose performance

On the base of analysis of the response kinetic peculiarities the physical mechanisms were considered, which determines the peculiarities of the adsorption-desorption processes at the interface. It was shown that adsorption of molecules from complex mixtures decays nonexponentially in general: in a “weak” adsorbers films it is exponential and approaches a stretched exponential for “strong” adsorbers film. Moreover the stretched exponentiality in adsorption-desorption processes can be described in terms of probabilistic model of relaxation based on the self-similarity of distributed random transition rates. We have demonstrated the first application of the stretched exponential low for nonexponential relaxations of QCM sensors with organic sensitive layers. There is a good agreement between molecular structure of materials, interfacial dynamics of sensors and discrimination ability of massifs thereon.