Orthorhombic <i>Fddd</i> Network in Diblock Copolymer Melts

Abstract

For the first time a Fddd network structure is found in a\npoly(styrene-b-isoprene) (S-I) diblock copolymer melts by using small-angle\nX-ray scattering and transmission electron microscope, as predicted by Tyler et\nal. by using calculations with self-consistent field theory for diblock\ncopolymer melts. The phase diagram of the S-I exhibits the sequence of\nDisorder- Fddd-Lamellae with decreasing temperature. The measured unit cell\nparameters ratios (a,b,c) are (1:2.02:3.46), which agrees with the result of\nthe theoretical calculation.\n