The operating principle is generally consistent with low-frequency DBD plasma cleaners. Electrons gain energy from the external electric field and transfer energy to surrounding molecules via collisions, exciting or dissociating these molecules and triggering electron avalanches.

Electron avalanches propagate rapidly toward the anode. Once they develop to a certain extent, space charges inside the avalanche distort the original electric field and amplify the electric field at the head and tail of the electron avalanche. Benefiting from the high charge density within the avalanche, secondary electron avalanches are generated, which converge with the initial avalanche to rapidly expand the discharge area. Ultimately, filamentary micro-discharge channels with high conductivity are formed throughout the entire discharge gap.

When RF-DBD plasma acts on material surfaces, physical and chemical reactions take place simultaneously as follows:

1. Cleaning effect: Physical etching and chemical reactions vaporize contaminants coated on the material surface;

2. Surface roughening to increase specific surface area;

3. Generation of free radicals and active sites on the material surface to endow the surface with chemical reactivity;

4. Cross-linking reactions between free radicals on the material surface;

5. Grafting of polar functional groups via reactions between surface free radicals and active species in the discharge space.

Ionization of different working gases produces distinct active species, leading to different surface modification results for materials. Nevertheless, the above mechanisms remain identical and occur concurrently.

Characteristics of RF Dielectric Barrier Discharge Wide-width Plasma Cleaner

RF dielectric barrier discharge is an optimal plasma discharge technique for material surface modification, with three core features:

1. The elevated discharge frequency increases the oscillation times of electrons between electrodes per unit time, facilitating the generation of high-energy electrons. Accordingly, its breakdown voltage is lower than that of low-frequency discharge under identical air pressure. Furthermore, the high-frequency alternating electric field intensifies electron oscillation and collision, which promotes the formation of multiple electron avalanches.

2. The dielectric layer sandwiched between two electrodes prevents localized arc discharge and sparking inside the discharge gap, ensuring safe plasma treatment. Pulse-modulated discharge can be adopted to resolve the trade-off between discharge stability and discharge intensity.

3. External parameters (electrode size, discharge gap, discharge power, etc.) can be adjusted to control electron density and average kinetic energy within plasma, so as to optimize the micro-discharge channels.

RF wide-width DBD plasma cleaners boast broader application prospects than corona discharge devices, glow discharge equipment and low-frequency DBD plasma equipment:

• Corona discharge can generate plasma under atmospheric pressure, yet its plasma distribution is extremely uneven (concentrated only in high-field regions) with weak discharge and low efficiency, making it unfit for large-scale industrial production.

• Glow discharge produces uniform plasma but requires a vacuum system, resulting in high costs, high energy consumption and low productivity, which is incompatible with continuous industrial manufacturing.

• Low-frequency DBD operates without vacuum equipment, yet uniform discharge cannot be maintained when the discharge voltage rises.

By contrast, RF-DBD combines the atmospheric-pressure working advantage of corona discharge and the uniform & stable discharge performance of glow discharge.