Grazing incident small angle x-ray scattering study of polymer thin films with embedded ordered nanometer cells
writer：Yokoyama H (Yokoyama, Hideaki), Dutriez C (Dutriez
keywords：ORGANOSILICATE DIELECTRIC FILMS; SUPERCRITICAL CARBON-DIOXIDE; BLOCK-COPOLYMER; REFLECTIVITY; LAYER; ISLANDS; GISAXS; CO2
source：期刊
Analysis of nanostructures is of increasing importance with advances of nanotechnology. Embedded nanostructures in thin films in particular are of recent interest. Grazing incident small angle x-rayscattering GISAXS has been recognized to be a powerful method to probe such embedded nanostructures; however, quantitative analysis of scattering pattern is not always trivial due to complex refraction and reflection at surface and interfaces. We prepared nanocellular thin films using block copolymer template with carbon dioxide CO2; CO2 “bubbles” were formed in the CO2-philic block domains. Such nanocellular structures were analyzed by GISAXS and simulated using distorted wave Born approximation DWBA. Unlike traditional transmission x-ray scattering, GISAXS requires a careful choice of incident angle to analyze the form factor of scatters embedded
in a thin film. Nevertheless, the GISAXS measurements under optimized geometry with quantitative calculations using DWBA revealed that the nanocells are spherical and aligned in a single layer of hexagonal lattice and are surrounded by CO2-philic block domains.