DIBLOCK COPOLYMERS UNDER CONFINEMENT

The confinement of symmetric, diblock copolymers of perdeuterated polystyrene, d-PS, and poly(methyl methacrylate), PMMA, was investigated by neutron reflectivity. For the cases studied, where there is a strong interaction of one of the blocks with the interfaces, a multilayered structure comprised of alternating layers of d-PS and PMMA was found. The constraint placed on the copolymer by the film thickness was relieved by either compressing or expanding the fundamental repeat period of the copolymer. This corresponds to a contraction or expansion of the copolymer chains normal to the interfacial planes.