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

• Published in: Plasma processes and polymers 2023-05, Vol.20 (5), p.n/a
• Main Authors: Sui, Siyuan, Sun, Hongmei, Ni, Guohua, Liu, Yafeng, Zheng, Huan, Sun, Tao, Kong, Ling, Ma, Zhongyang, Yuan, Fangli
• Format: Article
• Language: English
• Subjects: Ammonia; anticoagulant; Argon; Ar‐H2O‐NH3 plasma; Density; Dopamine; Functional groups; Grafting; Heparin; Interlayers; Oxygen; Polymerization; Polytetrafluoroethylene; Thickness; Water vapor
• ISSN: 1612-8850; 1612-8869
• DOI: 10.1002/ppap.202200228

The 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. High‐performance heparin coating was prepared by plasma‐induced graft polymerization. The amount of oxygen grafted is the highest in samples treated with Ar‐H2O‐NH3 (a mixture of argon, water vapor, and ammonia) plasma compared to that treated with Ar‐H2O (argon mixed with water vapor) plasma. Higher content of oxygen‐containing groups on the polytetrafluoroethylene (PTFE) surface promotes the thickening and densification of polydopamine/polyethylenimide interlayer and ultimately contributes to the formation of a thick heparin coating on it. This technique provides a solution to the anticoagulant problem of blood contact implants that are made of polymer materials such as PTFE.