Spectroscopic investigation of the orientational heterogeneity of cellulose hydrate

Abstract

The spectroscopic method of attenuated total internal reflection in the IR region has been used to study the anisotropy in the absorption of commercial cellulose hydrate films. The relative change in molecular orientation in layers adjacent to the surface and in layers within the polymeric films have been assessed from the dichroism of the band at 1162 cm −1. It has been shown that the presence of a highly oriented sheath, whose degree of orientation and dimensions depend on the specimen thickness, is characteristic of the films. The lower orientation of the internal layers has been confirmed and it has been shown that there is a gradient in the molecular orientation, its distribution in the section being along the normal to the surface. The change in orientation on going from the surface to the internal layers is not monotonic in character. The existence of a maximum orientational heterogeneity across the section is peculiar to thin films of cellulose hydrate.