Deviation of early stage of spinodal decomposition from the Cahn-Hilliard-Cook theory observed in an isotopic polymer blend

Abstract The early stage of spinodal decomposition was studied by small-angle neutron scattering in the critical mixture of the isotopic blend deutero-polystyrene/polystyrene (d-PS/PS) of equal molecular volume of 1.42 × 10 6 cm 3 /mol. The time evolution of this process is described by the dynamical structure factor. The observed time evolution of the fluctuation modes is a non-exponential . The analysis of the data has shown that the non-exponential behavior was attributed to a time-dependent increase of the “range” of the Onsager coefficient.