Abstract
We investigate the microstructures of a recently developed tin oxide/polymer film [A. Wakabayashi et al.: Langmuir 23 (2007) 7990] by focused ion beam/transmission electron microscopy (FIB/TEM). The box-counting method is applied to microscopic images of composite layers with different tin oxide concentrations. The analysis indicates that chainlike clusters consisting of tin oxide nanoparticles and tin-oxide-depleted areas are formed in the layers. When the tin oxide concentration is decreased, the tin-oxide-depleted areas increase. However, the chainlike clusters maintain a similar fractal structure with dimensionality D∼1.4, irrespective of the tin oxide concentration. These results are consistent with the electroconductive behavior and the transparency of the film.