The dynamics of infinite nuclear matter in the conditions of density and temperature expected in the outermost layers of neutron stars is studied in the framework of a microscopic time-dependent mean-field approach around zero temperature. Dynamical processes in inhomogeneous nuclear matter are studied using a large number of nucleons in numerical simulations without any assumptions on the morphology of nuclear matter. The occurrence of exotic structures when varying internal conditions as densities, nuclear species and elementary cell symmetries is investigated. The corresponding structures are studied in terms of a phase diagram in density space evidencing some sensitivity to the isospin-dependent part of the equation of state.