ORDER IN THIN-FILMS OF SIDE-CHAIN LIQUID-CRYSTALLINE POLYMERS

Spin-coated side-chain liquid-crystalline polymer films, based on alte rnating copolymers of maleic anhydride and a-olefins carrying terminal mesogenic methoxybiphenylyloxy groups, on silicon wafers show lamella r ordering upon annealing above the glass transition temperature. In t he surface topography (atomic force microscopy measurements), structur es are visible with a height corresponding to a bilayer. Also within t he film, the side chains are ordered perpendicularly to the surface as measured by X-ray reflectometry. There are indications that directly at the substrate surface the side chains are aligned parallel to the s urface. By the two complementary techniques, a rather complete picture is obtained. Even though the films are very thin (nanometer-scale thi ckness), the structure has a high degree of perfection and the bilayer spacing is the same as measured for bulk polymer.