A novel experimental technique for three-dimensional (3D) visualization of phase-separated structure of polymer blend thin film was proposed. Polystyrene/poly(methyl methacrylate) (PS/PMMA) blend thin films with the thickness of approximately 100 nm were cut at extremely low angle by utilizing surface and interface cutting analysis system (SAICAS), and the cross-section was exposed as gradient surface with the width of approximately 2.5 mu m. SFM investigation for the grazing cross-section imaged the detailed internal and surface phase separated structure of the (PS/PMMA) blend thin films on one image. (c) 2007 Published by Elsevier B.V.