Enhanced performance of atmospheric pressure glow discharge enabled by dielectric porous anodic alumina

Thin dielectric barriers, in addition to controlling plasma contraction in radio frequency (rf) atmospheric pressure glow discharges (APGDs), also maximize the permissible discharge current, which boosts the production of reactive plasma species and enhances application efficacy. This study explores the optimization of porous anodic alumina (PAA) for the rf APGD and its application in enhancing the surface properties of polytetrafluoroethylene (PTFE). Utilizing a wet electrochemical process, we fabricated thin PAA layers on aluminum electrodes, significantly improving the stability and efficiency of rf APGD. The optimized anodizing conditions, particularly the applied voltage, were crucial in achieving the desired PAA film morphology. Our experimental results demonstrate that rf APGD with PAA dielectric electrodes maintains a stable, volumetric glow discharge across a broad current range. In γ mode, at a discharge current of 1.7 A, the electron density, excitation temperature, and gas temperature, measured using an equivalent electric circuit, the Boltzmann plot method, and the SPECAIR program, are 2.3 × 1011 cm−3, 5725 K, and 500 K, respectively. This configuration substantially enhances the hydrophilicity of PTFE surfaces, as evidenced by a decrease in water contact angle. This research showcases PAA electrode-assisted rf APGD as a cost-effective, efficient, and eco-friendly surface modification method.