Surface modification of polymers by 50 Hz dielectric barrier discharge (DBD) plasma produced in air at 40 Torr

Abstract

This study deals with the surface modification of polymer films utilizing a custom designed cost- effective dielectric barrier discharge (DBD) plasma produced in air at reduced pressure. We comprehensively examine diverse aspects of surface modification, encompassing electrical discharge characterization, optical signal analysis, contact angle measurements, and surface morphology assessment. Our observations unveiled the presence of distinctive filamentary streamer-based micro-discharges during the DBD process, with a power consumption of approximately 5.64 W and an electron density of 3.4 × 10¹¹ cm⁻³. Optical emission spectroscopy identifies multiple emission peaks attributed to nitrogen emissions. Notably, plasma treatment substantially reduced the water contact angle and augmented surface energy on polypropylene (PP) and polyethylene terephthalate (PET) films. Surface morphology analysis illustrated an increase in surface roughness following plasma treatment. Intriguingly, the initial rapid alterations in wettability and surface morphology attained equilibrium after approximately 30 s of treatment. This study highlights atmospheric DBD plasma's effectiveness in customizing polymer surfaces, improving wettability and roughness, offering promising applications for enhanced adhesion and wetting.