Fourier transform mid- and far-infrared specular reflectance studies of the polarizability of ion-containing polymers and oxidized polyethylene and its application to adhesion

Abstract

The dielectric properties of selected ion-containing polymers have been studied by specular reflectance spectroscopy through the mid- and far-infrared regions. These reflectance spectra and the resulting dielectric spectra were measured on (1) surface-oxidized and cation-exchanged polyethylene and bulk ionomers based on (2) ethylene-co-methacrylic acid copolymers, and (3) partially para-sulfonated polystyrene. The chemical nature of the near surface region and its response to applied fields was studied for these materials. The far-infrared spectra were studied to examine the interaction of metal cations with anionic sites, and the polarizability in the far-infrared was found to vary systematically with the identity of the cation. Adhesion forces resulting from dispersion interactions due to polarization mechanisms at mid- and far-infrared frequencies were calculated by Lifshitz theory for polymer–Pyrex glass substrate pairs.