Plasma treatment

Plasma Treatment is a powerful technique for Surface Modifications addressed to enhance the biological compatibility on treated products.

Biomedical applications needs polymers that, besides satisfying the technical requirements of their application, offer biocompatibility; they need to react adequately in combination to the biological environment in which they are employed.

Given that biocompatibility involves the interaction between the device and the biological environment, surface modification techniques offer a great solution to this problem with the benefit of avoiding costly changes of materials.

Biomat’s plasma equipment consists in a vacuum chamber with one or more gas inlet (equipped with proper dosing systems), two electrodes connected to a RF (or different frequency) generator are located within the chamber in order to supply to the gas that flows between them the energy that excite its molecules generating the plasma.

Prior to treatment Biomat’s technicians evaluate:

• the client’s requirement (applications, properties, and cost)
•  item’s material assessment

The process:

1. articles to be treated are introduced into the chamber of the reactor
2. a fixed degree of vacuum is reached
3. a controlled flow of one or more gas(es) fills the chamber and is excited by the electrical discharge creating the PLASMA
4. the reactive species of plasma react with the surface of the device modifying its properties 

The process in general operates in a short time (from seconds to minutes) at practically room temperature, affecting only the surface of the parts that are treated.

Among Surface Modification Techniques that Biomat has tested over the years, cold Plasma Treatment has proven to be the best solution thanks to its characteristics:

• suitable for preparing hydrophilic or hydrophobic surfaces on a wide range of polymers
• suitable for surface cleaning/etching
• action limited to the surface layer without affecting the bulk properties of the material
• short exposition time (few minutes)
• low temperature: the process temperature is near to the room temperature, which avoids unwanted effects on the polymers
• flexibility: it works on a wide range of materials and applications (from degreasing of a metallic surface to deposition of a new polymeric layer)
• environment-friendly: the dry nature of the process means no pollution on the treated parts and no chemical effluents, after the treatment, the parts need no additional process
• economic

Depending upon the type of gas or vapor that is employed in the plasma process it is possible to obtain different effects:

• Plasma cleaning
  plasma removes every organic contaminant from the surface leaving a surface cleaned on a molecular scale. Suitable both for polymers and glass or metal
• Surface activation
  employs a reactive gas (e.g. O2, N2) which creates different functional groups modifying the hydrophilicity and the biochemical reactivity of the polymer’s surface plasma-induced grafting employs inert gases (e.g. Ar, He) which remove some atomic species from the basic polymer generating reactive and cross-linked surfaces
• Plasma deposition
  some gases (e.g. methane) can be plasma polymerised, coating the device’s surface with a thin layer of a different polymer

One of the most used applications of the COLD PLASMA Technology is the modification of the wettability of the polymers. Polymers usually show an unwettable surface (contact angle > 90°).

This property means that, whenever a good adhesion to the surface is required, a poor response is encountered and therefore the surface needs to be treated to reach acceptable adhesion levels. Examples of application where a good wettability is important are, for example:

• adhesion of biological molecules binding proteins for immunoassays application – Tissue Culture surfaces
• gluing
• inking
• painting

Since every type of polymer shows different properties, Biomat studies the treatment and application for each specific material, taking into consideration the following features:

• the raw material
• the shape of the part
• the application

Once assessed the intrinsic feature and properties of the item treated our scientist adjust the following parameters to reach the required result:

• type of gas(es)
• time
• power

Once the process is completed the products will be analyzed by our lab for uniformity, effectiveness of the treatment, durability of its effects during storage.

Biomat’s 25+ years of experience allowed us to offer customized plasma treatments made with our Plasma Reactor.

We study, develop and make Surface Treatments onto customers’ items to find the best solution in terms of technical and economical features.

Biomat has offered Hydrophilic Plasma Treatment on a wide range of articles for its clients. 

Some examples:

• PP products for PCR
• filters and membranes
• biochips
• glass slides

All the treated products have proven an improvement in their performance related to the biological activity thanks to the Plasma Treatment.

Contact us for more informations.