Optical probes of organic thin films: Photons-in and photons-out

The structure of γ-aminopropyltriethoxysilane (γ-APS) films deposited on mechanically polished iron mirrors from aqueous solutions has been investigated using reflection-absorption infrared spectroscopy. Films formed at the natural pH of 1% aqueous solutions of γ-APS (∼10.5) were about 120 A in thickness and were composed of highly hydrolyzed oligomers characterized by infrared bands near 1550 and 1480 cm −1 . These bands were assigned to NH 2 deformation modes in amino groups that were very strongly hydrogen bonded with silanol groups to form cyclic structures. Films formed at pH = 12 were characterized by infrared bands near 1580 and 1488 cm −1 that were assigned to deformation modes of NH + 3 groups obtained by essentially complete proton transfer from silanol groups to amino groups. In all cases the as-formed films were stable in a dry environment but exposure to atmospheric humidity disrupted the strong hydrogen bonding, enabling the oligomers to condense to form polysiloxanes.

The structure of γ-aminopropyltriethoxysilane films on iron mirrors

The structure of various imidazoles on the surfaces of copper and gold mirrors has been studied by Fourier transform infrared reflection–absorption spectroscopy in order to elucidate the molecular mechanisms of corrosion inhibition of metal surfaces by imidazoles. Heptadecylimidazole, undecylimidazole, phenylimidazole, and imidazole were used to investigate the orientation of the imidazole ring and the accompanying side groups. When a gold mirror was withdrawn slowly from an ethanol solution of undecylimidazole, the imidazole ring adsorbed onto the surface flatly and the C–C bond of the hydrocarbon chain became parallel to the surface. A similar trend was observed on all imidazole derivatives studied. The orientation of the outer layers was disturbed when the thickness was increased. With a copper mirror, the structure of the imidazole at room temperature depended on the method of adsorption. A slowly withdrawn sample showed a predominant complex formation whereby the solution placed dropwise on the coppe...

A study on the orientation of imidazoles on copper as corrosion inhibitor and possible adhesion promoter for electric devices

Formation and structure of epoxy network interphases at the contact to native metal surfaces

This review covers the theory and application of Fourier transform infrared spectroscopy to the characterization of polymers. The basic theory, the sampling techniques and the spectral operations are described. The applications discussed include the study of polymer reactions, polymer structure and dynamic effects.

Fourier transform infrared spectroscopy of polymers

Reflection-absorption infrared spectroscopy and ellipsometry have been used to determine the structure of films formed by an epoxy resin adsorbed from solution onto polished iron and copper mirrors. Films only about 15 A thick were obtained. The infrared spectra of these films were characterized by absorption bands near 1500 and 1240 cm−1. Consideration of the thickness of the adsorbed films as well as wetability, surface coverage and the relative intensities of the bands near 1500 and 1240 cm−1 indicates that the epoxy resin molecules are probably adsorbed with a vertical conformation where only a single oxirane oxygen atom is in contact with the surface.

S. L. Chen

Papers

Reflection-Absorption infrared spectroscopy and ellipsometry of epoxy films on metals