Frequently Asked Questions

What is a plasma ?

Plasma is the fourth state of matter (after solid, liquid and gas). A plasma is made of highly reactive energetic species. It is that reactivity that enables the functionalization of the substrate surface.

What are the advantages of cold plasma technology ?

Plasma treatments enable to durably functionalize surfaces and deposit high performance layers.
The processes are dry and economical in terms of consumable and energy.
Plasma stations developed by CPI can either be adapted and integrated into an existing production line or be an independent system thanks to the expertise of our partner (SPOOLEX).
This process doesn’t generate any increase of temperature that could damage the substrate, which makes it ideal to treat thermosensitive materials.
Finally, cold plasma only treats the surface of the material without modifying its bulk properties.

How to create a plasma ?

To obtain a plasma, energy must be supplied to the gas :
• Thermal energy: for hot plasma (several thousands of degrees)
• Electromagnetic energy: for cold plasma

How does plasma functionalize a surface ?

The functionalization depends on:
• the physico-chemical composition of the plasma,
• the quantity of energy
• the quantity of plasma species

The functionalization is given by chemical species:
- that are highly reactive in the plasma
- that have the potential to develop the needed functionalization.

Depending on the objective of the treatment it’s possible to control how those species interact with the surface
• the molecules do not stay on the surface: energy transfer leads to surface cleaning or activation
• the molecules are grafted locally on the surface: chemical properties transfer, the surface obtains new properties
• the molecules are grafted on the surface and create a 3-dimensional network: thin film coating

Atmospheric pressure plasma or low pressure plasma ?

The choice depends on the shape of the material to be treated.
At CPI, we use atmospheric pressure plasma to treat flat flexible materials in continuous roll to roll process (R2R). For 3D objects, we use low pressure plasma, more adapted to complex shapes.

Is it possible to incorporate a plasma station into an existing line ?

Yes. Our plasma stations can be incorporated into existing lines (In-Line). They can also be an independent treatment station (Off-Line), thanks to the knowledge of our partner Spoolex.

What is the difference between a plasma treatment and a corona treatment ?

The chemical composition of the plasma has a great influence upon the functionalization given to the surface.
In CPI plasma stations, the chemical composition of the plasma is precisely controlled (at a hundredth of a percent). This allows a rich chemistry and a wide range of applications.
A corona station only uses ambient air for creating a plasma: its chemical composition is fixed (N2/O2 - 80/20) and its humidity rate is constantly varying.

Corona treatment gives sufficient performances for some applications. Nevertheless, it has several limits and drawbacks:
It can generate only one type of treatment: oxidant and heterogeneous:
• It is aggressive for the surface and breaks the substrate molecular structure: the consequence is a short lifetime of the treatment and the possible creation of a low cohesion layer
• Because of this short lifetime, the next transformation must be done immediately after the corona treatment
• The power is the only parameter that can be modified, this is not always enough to obtain the needed performances
These features impose limits to the performances and applications of corona treatments.

- In CPI plasma stations, the chemical composition of the gas is automatically adjusted depending on the substrate, the functionalization and level of performance required:
• Higher performances : the purity and chemical composition of the gas we use enable us to obtain tailored and efficient functionalization
• Longer lifetime: The treatments are homogeneous and do not damage the substrate. This is why they can last several days, month or even years, depending on your need.
• Storage becomes possible: since the functionalization is stable in time, it is not necessary to do the next transformation immediately after treatment.
• Our stations are capable of doing corona treatments (when higher performance is not requested): in this case, the treatment is performed with ambient air.

These advantages of performance, diversity and adaptability allow CPI cold plasma stations to create innovative solutions for a large field of applications.

Cost ?

The investment for a cold plasma station mainly depends on:
- the dimensions of the product to be treated
- the line speed
- the needed functionalization
We invite you to contact us in order to establish a budget.

How do we proceed ?

Depending on the substrate and the needed properties, we select different chemical plasma compositions.
For each chemical composition, we test different dosages.
Each plasma trial is analyzed in order to identify the best treatment conditions.
We then send you a report of the treatment results and samples to make sure our treatments are compatible and efficient for your own application.
If you are satisfied with our treatment, we will help you to integrate our technology in your production facility.