Specular x-ray reflectivity studies of microstructure and ordering in self-assembled multilayers

Specular x-ray reflectivity has been used to probe the structures of self-assembled monolayers and multilayers deposited using a three-step siloxane-based self-assembly technique that is repeated to form periodic multilayers. In films containing up to ten trilayers, it is found that the film thickness increases linearly as a function of the number of trilayers with no observable change in the surface roughness. Bragg peaks corresponding to the inter-trilayer spacing are observed. Both of these results indicate high structural regularity in these self-assembled multilayers. In self-assembled films with different constituent molecular building blocks, substantial and unexpected changes in the film structure occur as a result of subtle changes in the layers.