Symmetric Diblock Copolymer Thin Films on Rough Substrates: Microdomain Periodicity in Pure and Blended Films

• DOI: 10.1021/ma702465t
• Publication Date: 2008-03-13T06:01:20Z
• Authors: Easan Sivaniah; Shinya Matsubara; Yue Zhao; Takeji Hashimoto; Kenji Fukunaga; Edward J. Kramer; Tom E. Mates
• Keywords: Lipid microdomain; Small-angle X-ray scattering

The lamellar dimension, D, for pure and blended block copolymer (BCPs) thin films of symmetric poly(styrene)-block-poly(methyl methacrylate) was measured using atomic force microscopy analysis surface patterns perpendicularly oriented structures. It approximately verified, SAXS AFM analysis, that perpendicular structures in bounded by a neutral roughened interface did not significantly alter the bulk phase separation thermodynamics. In case blends, it also verified there uniform distribution blend components throughout film. These checks allowed detailed comparison D as function number statistical segments (N) composition existing predictions experiments. BCPs we observed two characteristic regimes; strong (D ∼ N0.66) intermediate segregation regimes N0.85). addition, more complicated, weakly segregated regime where does scale N0.5 expected random coil. good agreement with theory when BCP from strongly were used. cases or segregating used, an alternative semiempirical analytical developed. ratio N exceeds ∼5, macrophase film smaller component remaining at air surface.