Defects in Lamellar Diblock Copolymers: Chevron- and Omega-shaped Tilt Boundaries

Abstract

We investigate symmetric grain boundaries in a lamellar diblock copolymer system. The form of the interface between two grains strongly depends on the angle $\theta$, between the normals of the grains. When this angle is small, the lamellae transform smoothly from one orientation to the other, creating the chevron morphology. As $\theta$ increases, a gradual transition is observed to an omega morphology characterized by a protrusion of the lamellae along the interface between the two phases. We present a theoretical approach to find these tilt boundaries in two-dimensional systems, based on a Ginzburg-Landau expansion of the free energy. Calculated order parameter profiles and energies agree well with transmission electron microscope experiments, and with full numerical solution of the same problem.

11 pages, 10 gzipped postscript and jpeg figures, published in PRE Vol. 61, March 2000

References in corpus (4)

• Minimal Surfaces, Screw Dislocations and Twist Grain Boundaries
• Interfaces of Modulated Phases
• The Lamellar-Disorder Interface : One-Dimensional Modulated Profiles
• Interfaces and Grain Boundaries of Lamellar Phases

Cited by in corpus (9)

• Computing optimal interfacial structure of modulated phases
• Surface induced ordering in thin film diblock copolymers: tilted lamellar phases
• Diblock copolymer ordering induced by patterned surfaces
• Diblock Copolymer Ordering Induced by Patterned Surfaces Above the Order-Disorder Transition
• Self Consistent Field Theory of Twist Grain Boundaries in Block Copolymers
• Role of Gaussian curvature on local equilibrium and dynamics of smectic-isotropic interfaces
• Coarse Graining in Block Copolymer Films
• Transition pathways in Cylinder-Gyroid interface
• Interfacial Phenomena of Solvent-diluted Block Copolymers