The thickness dependence of the order-to-disorder transition (ODT), measured by in situ grazing-incidence small-angle X-ray scattering (GISAXS), has been investigated in thin films of a symmetric polystyrene-b-poly(methyl methacrylate) (PS-b-PMMA) on a random copolymer (P(S-r-MMA)) grafted to the substrate where the interfacial interactions are balanced. With decreasing film thickness less than 25L0, the ODT significantly decreases to 193°C for film of 10L0 in thickness, because the interfacial interactions by a random copolymer grafted to the substrate provide a surface-induced compatibilization toward two block components. However, a plateau of the ODT at ∼213°C for films thicker than 25L0 was observed above the bulk value of 200°C. The elevation of this ODT indicates a suppression of compositional fluctuations normal to the film surface, more than likely because the dominant orientation of the lamellar microdomains was found to be parallel to the film surface.
Bibliographical noteFunding Information:
This work was supported by the Nuclear R&D Programs, APCPI ERC program (R11-2007-050-00000), and NRF grant (2010-0015410) funded by the Ministry of Education, Science & Technology (MEST), Samsung Electronics fund, Korea , Department of Energy (DOE), Office of Basic Energy Science, and the National Science Foundation ( MRSEC Program DMR-0520415 ), US.
All Science Journal Classification (ASJC) codes
- Organic Chemistry
- Polymers and Plastics
- Materials Chemistry