X-ray Reflectivity Study of Self-Assembled Thin Films of Macrocycles and Macromolecules

Abstract

The layer-by-layer growth of film structures consisting of sequential depositions of oppositely charged macromolecules (polymers) and macrocycles (ring-shaped molecules) has been carried out using the self-assembly technique. These self-assembled structures were characterized with X-ray reflectometry, results from which indicate (1) the average electron density of the sample measured after a sequential deposition of macromolecules followed by macrocycles remained the same regardless of the number of depositions made, while (2) the average thicknesses of alternately deposited macromolecules and macrocycles deposited at the beginning of the fabrication were larger than those deposited after many depositions and (3) the roughness of the growth surface generally increased with each deposition. These observations suggest that inorganic−organic interactions play an important role during the initial stages of thin-film growth, but less so as the thin film becomes thicker.