Effect of Short Diblock Copolymers at Internal Interfaces of Large Diblock Copolymer Mesophases

A model system of short polystyrene−polyisoprene diblock copolymers mixed with the corresponding strongly segregated long diblock copolymers is studied by small-angle X-ray scattering, electron microscopy, and self-consistent mean-field calculations of the ordered microphases. It is found that most of the small diblocks solubilize in the ordered domains, but a small amount segregates to the domain interfaces, in the manner of cosurfactants. …