Chemistry Reference
In-Depth Information
Table 5.1
General categorisation of plasmas
Categorisation
Type of Plasma
Plasma source
∑
Direct current plasma (DC plasma)
∑
Radio-frequency plasma (RF plasma)
∑
Microwave plasma (MW plasma)
Plasma gas
∑
Helium (He)
∑
Argon (Ar)
∑
Oxygen (O
2
)
∑
Nitrogen (N
)
2
∑
Ammonia (NH
)
3
∑
Carbon tetrafluoride/tetrafluoromethane (CF
)
4
∑
Air
Operational pressure
∑
Low-pressure plasma (Vacuum plasma)
∑
Atmospheric pressure plasma
∑
High-pressure plasma
Plasma temperature
∑
Low-temperature plasma
∑
High-temperature plasma
Table 5.2
Examples of the type of plasma gases, along with their effects
for the surface treatment
Plasma gas
Effect
∑
He, Ar
Introduce free radicals, which can react with O
2
or air to form peroxide and/or hydroperoxide.
(These functionalities can be used for initiation of a
polymerisation reaction.)
∑
Increase surface roughness
∑
O
, N
, NH
Introduce functional groups, which can be used to bind
polymers or other molecules
2
2
3
∑
Improve surface wettability
∑
CF
Introduce functional groups, which can be used to bind
polymers or other molecules
4
∑
Improve water repellency
Plasma can be operated under vacuum, in atmospheric pressure,
or high-pressure regimes [26]. Vacuum plasma is sometimes
classified as a subdivision of low pressure plasma, since the control
of pressure needed to create a perfect vacuum is hard, depending
on the vacuum equipment quality. This technology is widely
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