Micromorphological characterization of polymer-oxide nanocomposite thin films by atomic force microscopy and fractal geometry analysis

The purpose of this study was to evaluate the 3-D surface micromorphology of polymer-oxide thin films spin-coated from a composite of poly-methyl-methacrylate as the matrix and elongated titania nanorods as the filler particles. The surfaces of these composite films were investigated by atomic force microscopy and characterized by fractal geometry analysis. The effect of increasing loading of the fillers between 0 and 30% by weigth relative to the matrix was assessed. An increasing roughness was observed, with typical emergence of protruding ripples progressively extending into larger stripes. The amplitude parameters of the surfaces were determined by analysis of the height distributions. The fractal analysis of roughness revealed that the films have fractal geometry. Triangulation method based on the linear interpolation type was applied to determine the fractal dimension. A connection was observed between the surface morphology and the physical properties of the coatings as assessed in previous works.