Bulk spinodal decomposition studied by atomic force microscopy and light scattering

We report the first observation of bulk spinodal decomposition in polymer b lends using atomic force microscopy (AFM). The fracture of a phase-separate d thick film of tetramethyl bisphenol A polycarbonate (TMPC) and polystyren e (PS) is shown to induce a surface roughness that is resolvable by AFM. Th e resulting topography reproduces the spinodal morphology and is analyzed q uantitatively. We investigate simultaneously the surfaces and bulk of the T MPC/PS films, a blend known to exhibit surface-directed spinodal decomposit ion. 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 st ructures relevant to phase separation phenomena.