Nitrogen-Rich Plasma Polymer Coatings for Biomedical Applications: Stability, Mechanical Properties and Adhesion Under Dry and Wet Conditions

Plasma polymerized coatings (PP) are increasingly used for biomedical applications in contact with body fluids. We optimized and studied the stability, mechanical properties, and adhesion in air and aqueous media of amine (NH2)-rich PP in low-pressure r.f. plasma from [NH3/C2H4] mixtures (L-PPE:N). Quartz crystal microbalance with dissipation monitoring (QCM-D) revealed partial dissolution or water-uptake (swelling) in real-time in various solutions, which helped identify the best gas mixture ratio for compromise between stability and high concentration of (NH2) groups. Nanoindention revealed strong decrease of Young's modulus and hardness in water. Finally, a Cross-Hatch peel test was used to optimize L-PPE:N adhesion on poly(tetrafluoroethylene) (PTFE): plasma pre-treatment prevented both dry and wet delamination.