Angle resolved XPS characterization of cationic polyacrylamides

J. Zekonyte, R. L. Williams, G. Beamson, P. Weightman

    Research output: Contribution to journalArticlepeer-review

    Abstract

    In many applications surfaces are modified using polymer films and the polymers used are often complex copolymers. In biomedical applications it is critical to determine the surface properties of a substrate as it is these that mediate the cellular interactions. The surface structure of copolymer films can only rarely be established from their bulk composition alone. In this study angle resolved XPS was used to build a model of the structure of copolymer films produced on glass substrates from a family of poly(acrylamide) copolymers containing cationic blocks. The thickness of the copolymer films was demonstrated to be dependent on the concentration of the polymer solution and the ratio of non-cationic to cationic blocks in the copolymer. The data demonstrated that the cationic blocks of the copolymer preferentially segregated to the glass surface and the non-cationic poly(acrylamide) blocks preferentially segregated to the air–vacuum interface. A low concentration of the cationic functional groups was present throughout the poly(acrylamide) layer and it was suggested that this resulted from a small fraction of the cationic blocks being pulled into the poly(acrylamide) layer at points along the polymer chain where the two blocks are connected. Evidence of a thin surface hydrocarbon contamination layer was also observed.
    Original languageEnglish
    Pages (from-to)316-323
    JournalSurface and Interface Analysis
    Volume41
    Issue number4
    Early online date20 Jan 2009
    DOIs
    Publication statusPublished - Apr 2009

    Keywords

    • angle resolved XPS
    • cationic polyacrylamide
    • copolymer block segregation

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