Mechanisms of surface charge dissipation of silicone rubber enhanced by dielectric barrier discharge plasma treatments

Abstract

This paper investigates mechanisms of the surface charge dissipation of silicone rubber (SiR) after dielectric barrier discharge (DBD) plasma treatments in an open air. Electrical and physicochemical properties of the untreated and plasma treated samples were evaluated by surface and volume conductivity, surface potential decay (SPD) measurements, Fourier transform infrared (FT-IR), and water contact angle tests. Results show that the surface conductivity of the plasma treated samples evidently increases with the treatment time. The samples with a longer DBD plasma treatment time enhance the SPD rate after the positive and negative corona charging. However, an abnormal surface potential variation is observed at the beginning of the SPD after the negative corona charging. It is found that the top-bottom surface plasma treatment can further accelerate the SPD of the samples compared with the untreated and single surface plasma treated samples. The physicochemical analysis shows that the concentration of polar groups is increased after the plasma treatment, and the water contact angle is consistently declined with the increase of the plasma treatment time. The calculated trap distribution illustrates that the hole trap energy and the electron trap density of the sample are decreased after the plasma treatments. This investigation attributes the measured SPD of the untreated sample and single surface treated samples to the electrical conduction along the sample surface, but the SPD of the top-bottom surfaces plasma treated samples is enhanced by the charge neutralization and transportation through the material bulk as well as the sample top surface conduction.

Evidence of ionic film deposition from single‐filament dielectric barrier discharges in Ar–HMDSO mixtures

“…[57] Electrons are trapped on silicone rubber with binding energies <1 eV. [58] The energy released upon the recombination of PMDS + with a free electron is not known, 8 which probably will be not very different from the ionization energy of the trimethylsilyl radical, 6.5 eV. [60] The kinetic energy of the ions accelerated in the transient cathode fall, by comparison, is less; an estimation with an equation in the monography by Raizer [61] results in <1 eV.…”

Review of interface tailoring techniques and applications to improve insulation performance

“…In material modifications, atmospheric pressure non-thermal plasma is usually generated by dielectric barrier discharge (DBD) [21,23], radiofrequency plasma generator [64] and plasma jet (APPJ) [22,65] working gas in plasma modification to treat the material surface and found that the C-H bond is substituted by the C-F n bond on the treated surface. In studies by Shao et al [23] and Chen et al [21], the plasma treatment was conducted in open air, and it was found that the plasma introduces an O element into the polymer surface, and the chemical reactions produce carbonyl groups. It was found that the plasma treatment method with CF 4 and air as the working gas chemically modified the material surfaces in a manner similar to fluorination and ozonation; thereby, flashover strength can also be effectively improved.…”

“…open air) working gas can be used to treat material surfaces in a manner similar to that of direct fluorination and ozone treatment. In material modifications, atmospheric pressure non‐thermal plasma is usually generated by dielectric barrier discharge (DBD) [21, 23], radiofrequency plasma generator [64] and plasma jet (APPJ) [22, 65], as shown in Figure 4a,b. Lopez‐Garcia et al.…”

“…[23] and Chen et al. [21], the plasma treatment was conducted in open air, and it was found that the plasma introduces an O element into the polymer surface, and the chemical reactions produce carbonyl groups. It was found that the plasma treatment method with CF 4 and air as the working gas chemically modified the material surfaces in a manner similar to fluorination and ozonation; thereby, flashover strength can also be effectively improved.…”

“…Chemical modification is thought to be an effective method to tailor trap states in polymers. It is widely accepted that fluorination, ozone treatment and CF 4 /air plasma can reduce surface trap depth to accelerate charge dissipation along the material surface to improve flashover voltage [14, 15, 21–24, 30, 61, 63]. An et al.…”