Volume 43 (2010) Issue 4 Pages 406-412
This paper presents an immobilizing technique for copper ions on a substrate through a nanoscale thin film containing pyrrole groups. The nanoscale polypyrrole thin film covalently bonds to a substrate through a chemically adsorbed monolayer (CAM) containing pyrrolyl groups. We used 12-(1′-pyrrolyl)-n-undecyltrimethoxysilane (PUMS) as a chemical adsorbent molecule to form PUMS-CAM. Then a polypyrrole thin film was prepared on the PUMS-CAM by oxidative polymerization. For characterizing the PUMS-CAM and the polypyrrole thin film, we performed contact angle measurement, X-ray photoelectron spectroscopy (XPS), and film thickness measurement with ellipsometry. The water contact angles on the silicon substrate covered with PUMS-CAM and with PUMS-CAM and polypyrrole thin film were about 67.3° and 60.3°, respectively. XPS spectra exhibited binding energies of 285.0 eV for C1s and 400.0 eV for N1s. These results indicate that the PUMS-CAM and the polypyrrole thin film were prepared on the substrate. The film thicknesses of PUMS-CAM and polypyrrole thin film were approximately 1.5 nm and 2.3 nm, respectively; therefore, this indicated that PUMS-CAM and polypyrrole thin film were in the nanoscale. In addition, XPS was also applied to confirm the immobilization of the copper ions on the substrate. The results indicate the formation of the complex between the copper ions and the nitrogen atoms of the pyrrolyl groups. Therefore, this technique for immobilizing metal ions should be useful for many applications in plating industries.