Chemistry Reference
In-Depth Information
DC corona enables the generation of a very thin (
d
30 μm) up to 1.5 cm long
plasma filament at atmospheric pressure, which is adapted for treatment of small
cavities [273] (Figure 8.40b).
The plasma jets are applied for the treatment of selected small areas but of bodily
parts with complex geometries and small cavities. Furthermore, plasma jets can be
arranged in arrays to adapt on special geometries.
∼
8.2.3.5.1.2 Dielectric Barrier Discharges
The volume barrier discharge is characterized by the plasma in the gap in between
two by dielectric-separated electrodes (Figure 8.41a and b). The object to treat may be
used as the second electrode. Surface barrier discharge are excited by two electrodes
situated on an isolating surface or embedded inside the dielectric; the plasma is
generated on the dielectric surface. The subject under study is located nearby the
active plasma [109] (Figure 8.41c).
In a floating electrode dielectric barrier discharge (FE-DBD) [98], the treated
object serves as second active electrode in front of the dielectric-protected powered
electrode. This not grounded second electrode floats, see Figure 8.41a. This discharge
configuration enables charge carriers to hit directly the treated surface. Using a
surface barrier discharge, the plasma is ignited on the surface of a special electrode
arrangement. It can be brought close to the target to be treated, but the target is not
part of the electrode configuration.
The plasma of the DBD is suitable for the treatment of more extended regions.
(a)
(b)
(c)
FIGURE 8.41
Dielectric barrier discharges: (a) volume barrier discharge with stray capacity,
(b) volume barrier discharge with grounded electrode, and (c) surface discharge.
