Thin Film Morphologies of Bulk-Gyroid Polystyrene-block-polydimethylsiloxane under Solvent Vapor Annealing

Abstract

Thin film morphologies of a 75.5 kg/mol polystyrene-block-polydimethylsiloxane (PS-b-PDMS) diblock copolymer subject to solvent vapor annealing are described. The PS-b-PDMS has a double-gyroid morphology in bulk, but as a thin film the morphology can form spheres, cylinders, perforated lamellae, or gyroids, depending on the film thickness, its commensurability with the microdomain period, and the ratio of toluene:heptane vapors used for the solvent annealing process. The morphologies are described by self-consistent field theory simulations. Thin film structures with excellent long-range order were produced, which are promising for nanopatterning applications.

Widely Tunable Morphologies in Block Copolymer Thin Films Through Solvent Vapor Annealing Using Mixtures of Selective Solvents

“…Again, the surface was treated before the deposition and annealing of the diblock copolymer and etching was required to reveal the structures, and the final morphology was film thickness dependent. [13, 18] In more recent work, PS- b -PDMS with a starting synthesized double-gyroid morphology in the bulk was able to form spheres, cylinders and perforated lamellae in thin films through solvent annealing relying heavily on the film thickness and microdomain period [19] , a result that was also found by She et al . for the poly(styrene)- b -poly(L-lactic acid) system.…”

An in situ GISAXS study of selective solvent vapor annealing in thin block copolymer films: Symmetry breaking of in‐plane sphere order upon deswelling

“…Transitions from cylinders to spheres, from cylinders to perforated lamellae, and from gyroid to cylinders have been reported for BCP films upon annealing in selective solvent vapors. A wide range of morphologies can be obtained from the same BCP by means of SVA with either solvents of different selectivity, mixtures of selective solvents, or with mixed vapors of solvents with different selectivity for the respective blocks …”

Nanostructured Morphologies by Self-Assembly of Diblock Copolymers: A Review

“…Even if in the bulk state, the perforated lamellar morphology of block copolymers has been reported to be a metastable state of the gyroid (G) phase, under thin film confinement conditions, one-dimensional confinement provides stability to the phase [26,27] and has been found for different diblock copolymer thin films under several conditions [26][27][28][29][30][31][32][33][34][35]. For thin films of poly(styrene-b-dimethylsiloxane) (PS-b-PDMS) diblock copolymer spin coated onto silicon wafers modified with hydroxyl-terminated PDMS subject to solvent vapor annealing, depending on the film thickness, its commensurability with the microdomain period, and the ratio of toluene/heptane vapors used for the solvent annealing process, perforated lamellae morphology can be obtained [26], besides spheres, cylinders, or gyroids.…”

“…For thin films of poly(styrene-b-dimethylsiloxane) (PS-b-PDMS) diblock copolymer spin coated onto silicon wafers modified with hydroxyl-terminated PDMS subject to solvent vapor annealing, depending on the film thickness, its commensurability with the microdomain period, and the ratio of toluene/heptane vapors used for the solvent annealing process, perforated lamellae morphology can be obtained [26], besides spheres, cylinders, or gyroids. Even if PS-b-PDMS presented a double-gyroid morphology in bulk, as a thin film the morphology can be tuned by playing with different parameters.…”