Symptoms of SPTP are indistinct and preoperative diagnosis is often inaccurate. Magnetic resonance imaging improves SPTP diagnosis. In general, the prognosis of well-circumscribed SPTP is favourable after curative resection.
The orientation of lamellar microdomains and phase transition for the thin films of a symmetric polystyrene-b-poly(methyl methacrylate) (PS-b-PMMA) on random copolymer-grafted substrates were investigated by transmission electron microscopy (TEM) and grazing-incidence small-angle X-ray scattering (GISAXS). The styrene mole fraction (X S ) in random copolymers of P(S-r-MMA) was controlled to tune the interfacial interactions at the substrates from PS-selective to PMMA-selective. Except in the case of a neutral substrate with X S ¼ 0.55, all the films showed the parallel orientations of lamellar microdomains, which were validated by the TEM images. However, the GISAXS analysis of PS-b-PMMA films indicated that the intensity ratio of the out-of-plane scattering to the in-plane scattering can be a sensitive indicator for evaluating the degree of orientation of lamellar microdomains or surface neutrality at the substrates. The orientation of lamellar microdomains on a neutral substrate was influenced by the film thickness and molecular weight of PS-b-PMMA, which results from predominantly the entropic contribution to the free energy in competition between the chain-end effect and nematic term. Intriguingly, the order-to-disorder temperature (ODT) of PS-b-PMMA films on a series of the substrates shows a minimum at X S ¼ 0.55. The ODT measurements, a new approach to evaluating the interfacial interactions at substrates, confirm that a neutral substrate induces surface compatibility between the PS and PMMA blocks at the substrate.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.