Local defects in thin polymer films: a scanning sub-microbeam grazing incidence small angle scattering investigation

Micro-cracks induced by evaporation-assisted flow of a polymeric blend solution are investigated. After evaporation of the solvent toluene, the blend film of polystyrene and poly-n-buthylacrylate exhibits small cracks aligned perpendicular to the original flow direction. The local defect in the elsewhere rather continuous blend film is probed with atomic force microscopy. With scanning sub-microbeam grazing incidence small angle X-ray scattering a position sensitive surface scattering experiment is presented. Due to the beam diameter of 0.9μm the local micrometer sized defect structure is resolved.