Top: Neutron reflectivity data from annealed asymmetric block copolymer film.
Bottom: Corresponding schematic model shows the distribution of the dPS minority block and PBMA in the film; there is a co-existence of cylindrical and lamellar domains.
Bottom: Corresponding schematic model shows the distribution of the dPS minority block and PBMA in the film; there is a co-existence of cylindrical and lamellar domains.
Scientific Achievement
Dispersity and asymmetric interactions with substrates facilitate co-existence of cylindrical and lamellar domains in thin films of diblock copolymers.
Significance and Impact
Work establishes dispersity as an important parameter in realizing co-existing nanoscale domains and for tailoring properties of thin films containing diblock copolymers.
Research Details
- Copolymer thin films containing asymmetric poly(deuterated- styrene-b-n butyl methacrylate) – dPS-PBMA - were studied using specular neutron reflectivity (NR) and self-consistent field theory (SCFT).
- Obtained co-existing cylindrical domains near the silica substrate and lamellar domains near the air interface.
- Vertical segregation based on chain lengths led to stabilization of the co-existing domains.
J. P. Mahalik, W. Li, A.T . Savici, S. Hahn, H. Lauter, H. Ambaye, B. G. Sumpter, V. Lauter, and R. Kumar, "Dispersity-Driven Stabilization of Coexisting Morphologies in Asymmetric Dibloc Copolymer Thin Films," Macromolecules 54, 450-459 (2021). DOI: 10.1021/acs.macromol.0c01722
