Lamellar microdomain orientation and phase transition of polystyrene-b-poly(methyl methacrylate) films by controlled interfacial interactions

摘要: The orientation of lamellar microdomains and phase transition for the thin films a symmetric polystyrene-b-poly(methyl methacrylate) (PS-b-PMMA) on random copolymer-grafted substrates were investigated by transmission electron microscopy (TEM) grazing-incidence small-angle X-ray scattering (GISAXS). styrene mole fraction (XS) in copolymers P(S-r-MMA) was controlled to tune interfacial interactions at from PS-selective PMMA-selective. Except case neutral substrate with XS = 0.55, all showed parallel orientations microdomains, which validated TEM images. However, GISAXS analysis PS-b-PMMA indicated that intensity ratio out-of-plane in-plane can be sensitive indicator evaluating degree or surface neutrality substrates. influenced film thickness molecular weight PS-b-PMMA, results predominantly entropic contribution free energy competition between chain-end effect nematic term. Intriguingly, order-to-disorder temperature (ODT) series shows minimum 0.55. ODT measurements, new approach substrates, confirm induces compatibility PS PMMA blocks substrate.