Surface structure of polycarbonate urethanes visualized by atomic force microscopy

Polycarbonate polyurethanes are utilized for the production of long-term biomedical implants. The thermodynamic incompatibility between the hard and soft segments that make up these materials induces a two-phase microstructure. This two-phase structure (i.e. hard and soft segment phases) has unique features which contribute to its mechanical stability and moderate biocompatibility at the surface. As AFM was used to study the structure of six different polyurethane elastomers, where the reagent stoichiometries, as well as the chemistry of the hard segments, were changed. The results (especially phase-mode images) indicated that the microdomain structures depend on the hard segment chemistry and are relatively less dependent on the stoichiometry. This type of data could be used in the future to relate biological responses to the surface architecture and chemistry of polyurethanes.