Geometric strong segregation theory for compositionally asymmetric diblock copolymer melts

We identified the effect of the geometry imposed by the shape of the Wigner-Seitz cell or confinement domain in the strong segregation limit of diblock copolymer melts with strong composition asymmetry. A variational problem is proposed describing the distortions of the chain paths due to the geometric constraints. For cylindrical phases, we computed the geometric excess energies on hexagonal, square, and triangular domains in the plane orthogonal to the cylinder axis. Our results explicitly demonstrate that the hexagonal lattice of cylinders has the lowest energy for a fixed Wigner-Seitz cell area among the three possible periodic lattices covering the plane.