Characterization of interfacial phenomena occurring during exposure of a thin copper film to an aqueous suspension of an acidic polysaccharide

Abstract

A Fourier transform infrared spectrometer equipped with a cylindrical internal reflection element was used to sample the solid—liquid interface of a metallic copper film submerged in an aqueous acidic polysaccharide solution. The presence of a polysaccharide absorption band at 1050 cm−1 in a water-subtracted spectrum supported previous spectroscopic data indicating polymer accumulation at the surface of the film. Firm binding of the polysaccharide to the surface after a 17-day exposure period was demonstrated by the retention of the 1050-cm−1 absorption band in spectra obtained after gentle rinsing of the film surface with polymer-free water. The sampling technique also provided evidence which suggests that acidic polysaccharides, including the firmly bound exopolymers produced by adherent cells of a freshwater sediment bacterium, promoted deterioration of the copper film. Internal reflection Fourier transform infrared spectroscopy appeared to be a useful, nondestructive method to study the sorption of biomolecules to a solid metal surface submerged in an aqueous medium.