Surface Morphology Diagram for Cylinder-Forming Block Copolymer Thin Films
- National Institute of Standards and Technology (NIST)
- ORNL
We investigate the effect of annealing temperature (T), film thickness (hf) on the surface morphology of flow coated films of a cylinder forming block copolymer, poly (styrene-block-methyl methacrylate) (PS-b-PMMA). Surface morphology transitions from a perpendicular to a parallel cylinder orientation with respect to the substrate with increasing hf are observed in these model frustrated-interaction films where the substrate interaction is preferential for one of the blocks (PMMA) and nearly neutral for the other interface (polymer-air). In these films a transition occurs from cylinders oriented parallel to the substrate to a mixed or hybrid state where the two orientations coexist followed by a transition to cylinders oriented perpendicularly to the polymer-air interface for larger hf. The characteristic values of hf defining these surface morphological transitions depend on T and we construct a surface morphology diagram as a function of hf and T. The surface morphology diagram is found to depend on the method of film formation (flow coated versus spun cast films) so non-equilibrium effects evidently have a large effect on the surface pattern morphology. In particular, the residual solvent within the film (quantified by neutron reflectivity measurements) in the context of physics of glass-formation can have a large effect on the surface morphology diagram.
- Research Organization:
- Oak Ridge National Laboratory (ORNL); Center for Nanophase Materials Sciences
- Sponsoring Organization:
- SC USDOE - Office of Science (SC)
- DOE Contract Number:
- AC05-00OR22725
- OSTI ID:
- 942238
- Journal Information:
- ACS Nano, Journal Name: ACS Nano Journal Issue: 11 Vol. 2
- Country of Publication:
- United States
- Language:
- English
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