Angle resolved XPS characterization of cationic polyacrylamides

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.

Polyester textile functionalization through incorporation of pH/thermo-responsive microgels. Part II: polyester functionalization and characterization

“…Similarly, the theoretical values for a CM complex were calculated based on a 1:1 analogy of chitosan to PNIAA. Similar assumptions are reported in literature for copolymers of unknown degree of polymerization, based on which the grafting extent on surfaces or the surface fraction covered by a copolymer is determined [28]. If the PET RM surface was completely covered by PNIAA microparticles, its N/C ratio should be equal to the theoretical value of the PNIAA N/C ratio.…”