Multifractal Surface Characteristics of Thin, Gas-Sensitive, Copper-Containing Polyacrylonitrile Films

Using the atomic force microscopy method, the surface of thin, copper-containing polyacrylonitrile (PAN) films is studied. The distribution function over the height of the surface profile is analyzed by the method of multifractal detrended fluctuation analysis (MFDFA). The fractal dimension, correlation dimension, scaling exponent, and Hurst exponent (H) are used as parameters in this analysis. The results of studying the surface of thin, copper-containing PAN films by the MFDFA method confirm the assumption about the multifractal nature of the surface. Technological parameters in the production of films determine the frequency of occurrence of structures with different fractal dimensions on the film surfaces, which is reflected in the Hurst exponent. A bend is present in the multifractal spectrum in those cases when the films show gas sensitivity with a coefficient ofS= 0.35 or higher.