Orientational order near the boundaries of glassy diane-based oligomers with the surrounding phases

Abstract

Spontaneous birefringence and IR spectroscopy were used as methods for studying a homologous series of diane-based oligomeric polyhydroxyethers. Orientational order has been found to appear near the spherical or planar interfaces between films prepared from oligomers with M n ⩾ 1500 and a solid substrate or air. Both the thickness of the oriented layer and the degree of orientation increase with increasing M n . The thickness also increases with increasing radius of curvature of the oriented surface, levelling off as the surface becomes planar. With rising molar mass the relative content of hydrogen-bonded hydroxyl groups declines. The observed rise in the degree of orientation with increasing molar mass has been attributed to the diminishing plasticizing effect of low-molar-mass fractions, combined with changes in the interaction between the terminal epoxide groups and hydroxyls situated in the central regions of the chain.