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Alcohol-induced structural transformations of cetyltrimethylammonium bromide (CTAB) aggregates adsorbed on mica have been investigated using atomic force microscopy (AFM). A series of alcohols of different chain lengths was used to study the effect on surface aggregate structure. In CTAB solutions of fixed concentration, increasing amounts of alcohol spread the lateral spacing of the CTAB cylinders adsorbed on mica. At high alcohol concentrations, relative to the alcohol chain length, the surface aggregates changed from a cylindrical to a spherical structure. This structural transformation is explained by hydrophobic interactions between the alcohol and surfactant micelle.

Polyphenylene oxide (PPO) films have been investigated as protective coatings and as selective inhibitors to permeants.1,2,3 These films have been shown to be passivating materials and therefore are potentially interesting for a variety of applications. It is important for further applications to be able to measure the thickness of thin films by nondestructive techniques, which is the subject of this report. In this study PPO films of various thicknesses were electrodeposited on highly oriented pyrolytic graphite (HOPG) electrodes and examined by spectroscopic ellipsometry (SE) and atomic force microscopy (AFM). These techniques are combined to yield the thickness of the polymer film and the optical properties of the HOPG substrate and the PPO overlayer in the visible and near ultraviolet spectral region.

Polyphenylene oxide (PPO) films electrochemically deposited on highly oriented pyrolytic graphite (HOPG) have been investigated by spectroscopic ellipsometry (SE) and atomic force microscopy (AFM). The optical properties of the substrate and film were measured over the visible and near UV spectral ranges. PPO film thicknesses were deduced from SE measurements and compared to results obtained by AFM. Spin cast linear PPO films were also measured. We demonstrate the AFM measurements are concordant with and useful for the interpretation of the ellipsometric measurements. The refractive index in the visible light region for the electrodeposited PPO films is 1.721 -i 0.006 and for the linear PPO films is 1.698 -i0.028.