Curvature as a guiding field for patterns in thin block copolymer films

Abstract

Experimental data on thin films of cylinder-forming block copolymers (BC) -- free-standing BC membranes as well as supported BC films -- strongly suggest that the local orientation of the BC patterns is coupled to the geometry in which the patterns are embedded. We analyze this phenomenon using general symmetry considerations and numerical self-consistent field studies of curved BC films in cylindrical geometry. The stability of the films against curvature-induced dewetting is also analyzed. In good agreement with experiments, we find that the BC cylinders tend to align along the direction of curvature at high curvatures. At low curvatures, we identify a transition from perpendicular to parallel alignment in supported films, which is absent in free standing membranes. Hence both experiments and theory show that curvature can be used to manipulate and align BC patterns.

References in corpus (5)

• Towards a Tetravalent Chemistry of Colloids
• Surface free energies for nematic shells
• Geometric Theory of Columnar Phases on Curved Substrates
• Extrinsic Curvature, Geometric Optics, and Lamellar Order on Curved Substrates
• Fluctuating Membranes with Tilt Order

Cited by in corpus (7)

• Geometry of Bend: Singular Lines and Defects in Twist-Bend Nematics
• Dynamic self-consistent field approach for studying kinetic processes in multiblock copolymer melts
• Effect of Sinusoidal Surface Roughness and Energy on the Orientation of Cylinder-Forming Block Copolymer Thin Films
• Model of the dynamics of an interface between a smectic phase and an isotropic phase of different density
• Substrate curvature governs texture orientation in thin films of smectic block copolymers
• Stability and Elasticity of Ultrathin Sphere-Patterned Block Copolymer Films
• Self-assembly of anisotropic particles on curved surfaces