Nanoparticles in block-copolymer films studied by specular and off-specular neutron scattering

For the design of multicompositional materials with a spatially defined order of different components symmetric polystyrene(deuterated)-block-polybuthyl methacrylate P(Sd-b-BMA) lamellar thin films are used as a structure-directing matrix for the nanoparticle arrangement. A P(sd-b-BMA) diblock-copolymer film spontaneously self-assembles upon annealing into a lamellar multilayer and orders the PS-coated nanoparticles, incorporated into the polymer solution prior to annealing, in a periodic lamellar structure. Specular reflection and off-specular neutron scattering were applied to determine the distribution of magnetite Fe₃O₄ nanoparticles in a symmetric P(Sd-b-BMA) film with a concentration of the nanoparticles of 7% of the volume fraction. From the experiments on neutron specular reflection and off-specular scattering, we obtained information about the distribution of the nanoparticles within the lamellae and about the distortion of the lamellar order of the copolymer matrix.