Formation and structure of organized molecular films for fluorinated comb copolymers

The molecular orientation in monolayer and multilayer films of fluorinated comb copolymers with various monomer ratios can be characterized by in-plane and out-of plane X-ray diffraction (XRD), near-edge X-ray absorption fine structures (NEXAFS) spectroscopy at the C K-edges, and atomic force microscopic observation. And further, the fine structure in the solid state and phase transition behavior of newly synthesized comb copolymers having fluorocarbon and hydrocarbon side-chains were investigated by temperature controlled wide-angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC). From the WAXD profiles, two kinds of short spacing peaks based on the formation of the sub-cell for fluorinated and hydrogenated side-chains were confirmed at 5.0 and 4.1 angstrom, respectively. Furthermore, two kinds of endothermic peaks, which corresponded to melting peaks of both side-chain crystals, appeared in the heating process of the DSC thermograms. From these experimental findings, the phase separation structure having the independently packed immiscible side-chain crystalline formed in the whole polymer crystal. In addition, it was found that these comb polymers formed highly ordered (double) layer structures estimated using WAXD and small-angle X-ray scattering (SAXS). These fluorinated comb copolymers form the monolayer on the water surface and their transferred film with phase separated structure at nanometer size on the solid. There were hydrogenated domains at 10-20 nm diameter scales in these phase separated surface structures of the monolayers. From these experimental results, these copolymer monolayers are expected to be used as in new molecular devices such as nano-lithography based on the surface patterning of polymer nano-materials. Copyright (c) 2006 John Wiley & Sons, Ltd.