Crystals made of close-packed polymeric spheres: A neutron scattering study on latex films

Abstract

The dense packing of polymeric spheres in latex films has been investigated by means of small-angle neutron scattering. The films were prepared by evaporation of the water out of a dispersion consisting of monodisperse charged particles (diameter 130 nm). Analysis of the Bragg peaks found in the scattering reveals that the particles are arranged in a face-centered-cubic lattice structure with well defined crystalline domains. Furthermore, it is found that the system still owns a memory of its initial structure upon prolonged annealing at temperatures far above its glass temperature. An interesting suppression of some Bragg peaks due to the influence of the particle scattering form factor is observed.