Ar‐H2O‐NH3 plasma grafting and polymerization of dopamine onto polytetrafluoroethylene to promote heparin immobilization

Abstract

AbstractThe surface of polytetrafluoroethylene (PTFE) is activated by argon (Ar), Ar mixed with water vapor (Ar‐H2O), and a mixture of Ar, water vapor, and ammonia (Ar‐H2O‐NH3) plasmas and then grafted onto polymerized dopamine/ethylene imine and immobilized heparin. Oxygen‐containing functional groups are all introduced onto the PTFE surface treated by three types of plasma. The amount of oxygen grafted is the highest in samples treated with Ar‐H2O‐NH3 plasma compared to that treated with Ar‐H2O plasma. An increase in the content of oxygen grafted onto PTFE contributes to an increase in the thickness and cross‐linking bond of the polymeric interlayer and then raises the density of the heparin coating. The thickness of the polydopamine/polyethylenimide intermediate layer on the surface of PTFE treated with Ar‐H2O‐NH3 plasma is 4.8 ± 0.3 μm, and the density of the immobilized heparin coating was 95 μg/cm2.