Distributions of Deuterated Polystyrene Chains in Perforated Layers of Blend Films of a Symmetric Polystyrene-block-poly(methyl methacrylate)

We have examined the spatial distributions of polymer chains in blend films of weakly segregated polystyrene-block-poly(methyl methacrylate) [P( S-b-MMA)] and deuterated polystyrene (dPS). By fine-tuning the composition (phi(PS+dPS) = 63.8 vol %) of the total PS/dPS component and annealing temperature (230 and 270 degrees C), P(S-b-MMA)/dPS blend films mainly form perforated layers with a parallel orientation (hereafter PLs(//)). The distributions of dPS in PLs(//) were probed by grazing-incidence small-angle neutron scattering (GISANS) and time-of-flight neutron reflectivity (ToF-NR). GISANS and ToF-NR results offer evidence that dPS chains preferentially locate at the free surface and within the PS layers for blend films that were annealed at 230 degrees C. Upon annealing at 270 degrees C, dPS chains distribute within PS layers and perforated PMMA layers. Nevertheless, dPS chains still retain a surface preference for thin films. In contrast, such surface segregation of dPS chains is prohibited for thick films when annealed at 270 degrees C.

Automated summary

By fine-tuning the composition and annealing temperature of blend films, the spatial distributions of polymer chains were examined. The surface preference of dPS chains varied under different annealing conditions for thin and thick films.