Modification of a polystyrene brush layer by insertion of poly(methyl methacrylate) molecules
(Color online) Water contact angles of PS brushes before any modification, PS brushes modified with PMMA-OH , and PS brushes treated with PMMA .
NEXAFS spectra of (a) PS and PMMA reference samples and (b) PS-OH brush modified with PMMA-OH (S3M20).
(Color online) Thickness of PS brushes before and after PMMA-OH modification, as a function of molecular weight of PS. The brush thickness increased as PMMA-OH was inserted into the PS brush.
(a) Chain densities of PS-OH and PMMA-OH in the final brushes. (b) PMMA-OH chain density as a function of PS initial brush thickness. (c) The ratio of PS in the final blend brush, , on the substrate. Shadow area highlights nonpreferential wetting brush compositions.
Top down SEM images of self-assembled P(S- -MMA) films on brushes: (a) S3M20, (b) S6M20, (c) S9M20, and (d) S20M20. On brushes S3M20 and S6M20, P(S- -MMA) formed fingerprints only, indicating that these brushes were nonpreferential to PS and PMMA. Partial parallel lamellae formed on PS-preferential wetting brushes S9M20 and S20M20. All SEM micrographs represent a area.
NEXAFS spectrum of PMMA-OH brush modified with PS-OH (M20S3), and the corresponding fitting to determine PS fraction in the final brush.
Molecular weight and polydispersity index of the polymers used.
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