What is Plasma Surface Modification?

Surface Modification of Plastic
Plasma surface modification can be used to make an object hydrophilic.
Any process by which a product’s surface is modified to accept either a bond or an ink for printing is commonly referred to as plasma surface modification.

These processes are used to make an object hydrophilic (wettable).

A hydrophobic surface will repel water and is considered non-wettable. Duck feathers, for example, are hydrophobic. Water will bead up and roll off instead of soaking into the feather.

A hydrophilic plasma treatment is often used on Teflon or plastics to make a surface more "wettable", which in turn increases bondability and printablility. This is our most common goal when implementing a plasma strategy.

Our plasma technology actually modifies the first few monolayers of the material, leaving free radicals on the surface and allowing it to bond to glue or ink.

This is especially useful when bonding different surfaces such as plastic and metal. The dissimilar surfaces favor different bonding agents. This can make finding a suitable bonding agent especially difficult.

By modifying the surface with plasma, an extra electron is left behind on the surface of the plastic or rubber, seeking out a connection. This allows the surface to adhere to the bonding agent with significantly increased strength.

Glossy plastic surfaces are often printed on or bonded to other materials such as plastic or metal handles. When these glossy surfaces are treated with plasma, the increased surface energy allows them to be printed on without smearing.

The effects are fairly temporary, ranging from just a few hours to a few days, plenty of time to complete the manufacturing process on the materials being treated.

Vacuum plasma surface treatment, such as oxygen plasma treatment, is superior to atmospheric pressure plasma technologies. Vacuum plasma systems allow the effects of the plasma to last longer and provide a superior level of surface improvement. Atmospheric Plasma Systems are generally more convenient to mounting on an assembly line, or treating a small area of a large product.

Plasma Etch manufactures industry leading plasma etching systems and plasma cleaning equipment. We can configure your system for surface modification along with other cleaning or etching applications.

Any configuration we build can be run with argon plasma or nearly any other gas for cleaning applications.

Industrial Uses

This type of plasma is generally used in a manufacturing environment. Plastic or metal are treated with plasma and then bonded to a handle or other apparatus.

For printing, treated plastic, Teflon or metal can be printed on, and the ink will permanently bond to the material.

With the frequency settings and pressures used for surface treatment, the plasma is only able to change the surface of the material. The effects are observed on a region only several molecular layers deep and the bulk properties of the material are unchanged.

Printing on untreated plastic or Teflon results in a poor quality finish and excessive amounts of ink failing to adhere to the surface. Creating a mess both at the time of printing and in the future when the product is handled.

Gases Used for Surface Modification

In order to get the bonding or printability that is desired, it is important to use the correct gas in the plasma equipment. We have a vast array of experience with plasma chemistry, and we can help you with your particular project.

Hydrogen is used for Teflon products, while nitrogen is often mixed in to create a custom blend of hydrogen and nitrogen gas. Oxygen is generally used for plastic products. To treat metal we generally add argon to prevent oxidation.

Oxygen and Argon are often used for plasma surface modification. Both gases are inexpensive to purchase, and oxygen can be produced on site from ambient air with an oxygen generator. Argon or hydrogen may be purchased from a local supplier.

All of our plasma cleaning systems are able to run nearly any gas or any combination of gases. Our larger plasma systems are available with up to 5 gas inputs.

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