Some experimental and theoretical aspects of structure and bonding in a series of polyalkyl acrylates and methacrylates studied by ESCA

Abstract

The core and valence levels of a series of polyalkyl-acrylates and polyalkyl, and aryl raethacrylates have been studied by ESCA. From an analysis of the individual component peaks for the C(_1s) and O(_1s) core levels and from a comparison of the relative area ratios it is shown that ESCA may be applied to the study of the immediate surface compositions of these acrylic systems. The results presented suggest that on the ESCA depth profiling scale the technique statistically samples the repeat units with no evidence for preferential orientation of the side chains at the surface. For some systems ESCA provided evidence for a degree of surface oxidation and hydrocarbon contamination. The valence levels of the acrylic polymers are shown to be characteristic of the particular polymer and can be used for identification of the isomeric configuration of the alkyl groups. The measured absolute and relative binding energies of the core levels of the polymer systems have been compared with a series of simple model compounds and different conformational configurations of models of polyacrylic acid and polymethyl-acrylate within the semi-empirical CNDO/2 SCF MO formalism using the charge potential model.