Elastic TiN coating deposited on polyurethane by pulsed laser

Titanium nitride (TiN) is regarded as a potential biomaterial for blood-contact applications. TiN thin layers were fabricated by pulsed laser deposition with the Nd:YAG laser on biologically applied polyurethane. Transmission electron microscopy (TEM) study of 250-nm-thick layers revealed columnar structure. Such layers were observed to be brittle, which led to crack formation and secondary nucleation after bridging. In order to improve the coatings elasticity, the thickness was reduced to 50 nm, which limited the deposition mechanism operation to the early stage. TEM cross-section observation revealed elastic properties of the thin layers. Conventional texture examinations as well as texture tomography were carried out for examinations of the deposited TiN layer. A biological test showed that TiN surface layer produced on polyurethane is characterized by good biocompatibility and decreased surface affinity for cell adhesion, which is expected for and desirable in blood application.