Phase segregation and compatibilization dynamics of multicomponent polymer films

Phase segregation dynamics and compatibilization is studied in blends of polystyrene (PS) and poly(methyl methacrylate) (PMMA). In low molecular weight symmetric blend systems, we observe two distinct scaling regimes, which are sensitively dependent on quench depth. A scaling exponent of α = 1/2 is observed at more shallow quenches, corresponding to diffusive coalescence in symmetric two dimensions binary fluids. At lower temperatures, α = 1/4 is observed, corresponding to a deep, critical quench where domain growth can only proceed via diffusion along domain boundaries. Segregated phases remain co-continuous and two-dimensional. For these systems, the dynamic scaling hypothesis is confirmed.; To restrict domain growth to two dimensions, it was necessary to develop and test three separate treatment techniques to form non-preferential annealing surfaces. The first method consists of adsorbing large molecular weight random copolymers to silicon oxide through hydrogen bond. We systematically establish that the copolymer remains for typical annealing experiments in blends of PS and PMMA if the −OH density at the surface is maximized before casting of the copolymer. A second technique utilized for surface modification was the vapor deposition of octyltrichlorosilane (OTS) onto silicon oxide surfaces. Preferential wetting of each homopolymer was achieved as well as neutrality. The third method utilizes hydroxyl-terminated, miscible, low molecular weight homopolymers of PS and PMMA covalently anchored to the substrate. We established a clear trend in surface coverage depending on the ratio of the brush materials.; We examine compatibilization dynamics in bilayers of PS and PMMA containing diblock copolymer. The diblocks in films below certain thicknesses will localize to the interface and the dynamics of such a phenomenon is examined. Initial domains by interfacial fluctuations grow initially with a typical power law (α = 1/3) growth, but the localization of diblock slows growth considerably in the late times. The entire process is described with a time dependent surface tension reduction and two separate data sets support this claim.