Silicone-coated polyimide films deposited by surface dielectric barrier discharges

Abstract

Hybrid dielectric barrier discharges are investigated for plasma generated on the surface of a dielectric layer, where two conducting electrodes of high voltage and ground are formulated on the upper and bottom surfaces. Using a flexible thin polyimide-film of a thickness ranging from 25 to 125 μm, a plasma is generated with a voltage of about 1 kV and a frequency of 40 kHz. However, the surface of the dielectric layer was etched through a chemical reaction involving plasma oxygen radical species, and thus the polyimide films failed readily, resulting in dielectric breakdown within short operating time ranging from a few minutes to several tens of minutes, based on the film thicknesses of 25 μm and 125 μm, respectively. These plasma erosions were prevented by coating the polyimide surface with a 25 μm thick silicone paste. The siliconecoated film surface was then reinforced remarkably against plasma erosion as the organic polymer was vulnerable to chemical reaction of the plasma species, while the inorganic silicone exhibited a high chemical resistance against plasma erosion.

Plasma skincare device based on floating electrode dielectric barrier discharge

“…The dielectric is a polyimide film of 125 μm thickness. The capacitance is estimated as C∼ε o KS/T, where T=125 μm is the dielectric thickness, the electrode area S≈S G =y 2 , and dielectric constant K=2.8 [13,14]. Using S=1 2 cm 2 , we calculate C=19 pF, which is of the same order as the values for y=1 cm listed in table 1.…”

“…Various structures of indirect devices have been developed, which range from plasma jets with syringe-needle electrode to large torches with different arrangements of the electrodes. Hybrid plasma sources were also suggested in a recent approach, which combines both techniques and allows flexible plasma designs [11][12][13][14].…”