Electroassisted Functionalization of Nitinol Surface, a Powerful Strategy for Polymer Coating through Controlled...

Area of Science:

• Biomaterials Science
• Surface Chemistry
• Corrosion Engineering

Background:

• Nitinol (NiTi) is attractive for biomedical applications but susceptible to corrosion and carcinogenic nickel ion release due to its nickel content.
• Polymer coatings and self-assembled monolayers (SAMs) are explored to improve NiTi surface properties and corrosion resistance.
• SAMs offer ordered structures that enhance corrosion resistance and enable surface functionalization for further modifications.

Purpose of the Study:

• To compare electroassisted, thermally assisted, and immersion methods for grafting 11-(2-bromoisobutyrate)-undecyl-1-phosphonic acid (BUPA) onto NiTi surfaces.
• To evaluate the effectiveness of BUPA grafting in improving NiTi corrosion resistance and enabling surface-initiated polymerization.
• To identify the most efficient and rapid method for BUPA SAM formation on NiTi.

Main Methods:

• Hydrothermal treatment of NiTi surfaces.
• Grafting of BUPA onto NiTi via electroassisted, thermally assisted, and immersion methods.
• Surface-initiated atom transfer radical polymerization (SI-ATRP) of 2-(dimethylamino)ethyl methacrylate on modified NiTi surfaces.

Main Results:

• Electroassisted grafting of BUPA at room temperature was the most effective method, achieving grafting in 5-10 minutes.
• The BUPA layer formed via electroassisted grafting significantly improved NiTi surface corrosion resistance.
• The modified NiTi surface successfully supported SI-ATRP for polymer grafting.

Conclusions:

• Electroassisted grafting is a rapid and promising technique for creating functional BUPA layers on NiTi surfaces.
• This method effectively enhances NiTi corrosion resistance, mitigating nickel ion release.
• The functionalized NiTi surfaces are suitable for subsequent polymerization, opening avenues for advanced biomedical devices.