Stability of the Gyroid Phase in Diblock Copolymers at Strong Segregation

E.W. Cochran, C.J. García-Cervera, and G.H. Fredrickson.


We report high resolution self-consistent field theory (SCFT) calculations that show the gyroid phase, Q230, to be stable in conformationally symmetric linear diblock copolymer melts prepared within the strong segregation regime, \chi N = 100, over a composition window of ~ 1.5%. This window broadens with the introduction of conformational asymmetry. The SCFT equations were solved using a novel pseudospectral approach with a plane wave basis and periodic boundary conditions. Saddle point field configurations were obtained using a semi-implicit Seidel relaxation algorithm. The modified diffusion equation was solved using a fourth-order backward differentiation formula and implicit treatment of the Laplacian operator. Our calculations are consistent with recent experimental observations of Q230 in strongly segregated diblocks.

Download the article: PDF format, or directly from Macromolecules.

Carlos J. Garcia-Cervera
Last modified: Wed Aug 22 19:51:57 PDT 2007