Enduring and Stable Surface Dielectric Barrier Discharge (SDBD) Plasma Using Fluorinated Multi-Layered Polyimide

Area of Science:

• Materials Science
• Plasma Physics
• Surface Engineering

Background:

• Polyimide (PI) films are widely used as dielectric materials in various applications, including plasma discharges.
• The operational lifetime of dielectric materials in plasma environments is often limited by degradation processes.
• Surface modification techniques are explored to enhance the performance and durability of dielectric materials.

Purpose of the Study:

• To investigate the effect of surface fluorination on the dielectric properties and lifetime of polyimide films in surface dielectric barrier discharge (SDBD).
• To analyze the impact of fluorination time on plasma stability and dielectric surface characteristics.
• To elucidate the physical and chemical mechanisms responsible for the enhanced dielectric lifetime.

Main Methods:

• Multi-layered polyimide films were surface fluorinated using a F₂/N₂ mixture at controlled temperature and pressure for varying durations (0, 30, 60 min).
• Fluorinated polyimide films were utilized as barrier dielectrics in surface dielectric barrier discharge (SDBD) in ambient atmospheric air.
• Characterization techniques included optical emission spectroscopy (OES), infrared thermography, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS).

Main Results:

• A significant extension in the dielectric lifetime of SDBD was observed after 60 minutes of surface fluorination.
• Optical emission spectroscopy revealed more stable plasma parameters (gas and electron temperature) with fluorinated polyimide dielectrics.
• Surface analysis indicated both physical changes (lowered surface temperature, increased roughness) and chemical modifications (grafting of fluorine groups) due to fluorination.

Conclusions:

• Surface fluorination of polyimide films is an effective method to enhance the dielectric lifetime of SDBD.
• The improved performance is attributed to a combination of physical surface modifications and chemical incorporation of fluorine.
• Stable plasma parameters achieved with fluorinated polyimide contribute to the extended dielectric durability in atmospheric air plasma applications.