ピロール系化学吸着単分子膜を介したポリピロール薄膜による銅イオンの固定

Abstract

A technique of immobilizing copper ions through a polypyrrole thin film that is covalently bonded to a substrate surface through a chemically adsorbed monolayer containing pyrrolyl group (PNN-CAM) was studied. Contact angle, Fourier transform infrared (FT-IR), UV-visible, and film thickness measurements were done to characterize the PNN-CAM and the polypyrrole thin film. The water contact angles on the slide glass changed from 4.5° to 67.0° by preparing the PNN-CAM. In the FT-IR spectrum for the slide glass covered with the PNN-CAM, strong bands attributable to the νasCH2 vibrations and νsCH2 appeared respectively at 2925 cm−1 and 2850 cm−1. These results indicate that PNN-CAM was prepared on the slide glass. In the subtracted UV-visible spectra before and after oxidative polymerization, a strong absorption band appearing at approximately 230 nm was assigned to the conjugated bonds of the polypyrrole groups. The result indicates that a polypyrrole thin film was prepared on the PNN-CAM. Measurements of the PNN-CAM and polypyrrole thin film using an automatic ellipsometer showed the respective thicknesses to be ca. 1.7 nm and ca. 2.1 nm. X-ray photoelectron spectroscopy (XPS) was also applied to confirm the immobilization of copper ions on the silicon substrate. Cu(2p) peak was observed from the silicon substrate covered with polypyrrole thin film after ultrasonic cleaning and wiping with wet cotton cloth. The result demonstrates the formation of the complex between the copper ions and the nitrogen atoms of the pyrrolyl groups.