Surface morphology of polypyrrole core polyacrolein shell latex by atomic force microscopy (AFM)

Polypyrrole latex (P(P)), synthesized in Redox polymerization of pyrrole, was used as seed for radical polymerization of acrolein initiated with K2S2O8. In this process the polypyrrole core/polyacrolein shell latex (P(P-A)) was obtained. Morphology of the surface of P(P-A) particles was investigated by atomic force microscopy (AFM). It was found that macromolecules of polyacrolein are ?or randomly distributed on the surface of polypyrrole but form patches. Apparently, attraction between macromolecules of polyacrolein in the surface layer is high and the enthalpy of formation of polyacrolein macromolecule clusters is sufficient to compensate, at least, the negative entropy change due to ordering of these macromolecules. Thickness of the polyacrolein layer on the surface of polypyrrole particles, which were covered only partially with polyacrolein, was equal to only 1.6 nm (standard deviation sigma = 0.2 nm) and thus, it was reasonable to assume that it corresponded to the monolayer coverage.