Bulk spinodal decomposition studied by atomic force microscopy and light scattering

We report the first observation of bulk spinodal decomposition in polymer blends using atomic force microscopy (AFM). The fracture of a phase-separated thick film of tetramethyl bisphenol A polycarbonate (TMPC) and polystyrene (PS) is shown to induce a surface roughness that is resolvable by AFM. The resulting topography reproduces the spinodal morphology and is analyzed quantitatively. We investigate simultaneously the surfaces and bulk of the TMPC/PS films, a blend known to exhibit surface-directed spinodal decomposition. The structure factors obtained from a BD-FFT of "bulk" AFM images and from time-resolved light scattering (LS) do not coincide-this is discussed in terms of the 2D (AFM) and 3D (LS) analysis involved. We finally compute general expressions relating 2D and 3D structure factors for a number of structures relevant to phase separation phenomena.