Hydrophilic Plasma Treatment

Plasma surface treatment of dental prosthetic structures (implant posts for example) has, for over a decade [1], been demonstrated to remove contamination and increase wettability which results in stronger bonding over the long-term.

Hydrophilic plasma coatings are a sub-category of plasma surface functionalization, the specific precursor being chosen to produce a permanent, high surface energy layer on the material or part being treated.  The hydrophilic surface is typically less than 1/100th thickness of a human hair, colourless, odourless and doesn’t affect the look or feel of the material in any way.

Permanent hydrophilic surfaces are employed for example in microfluidic devices to improve fluid flow and in many examples of life science for protective coatings, barrier layers and to improve biomolecular absorption.

In plasma coating, a nano-scale polymer layer is formed over the entire surface area of an object placed in the plasma. The coating process takes just a few minutes. The coating produced is typically less than 1/100th thickness of a human hair, colourless, odourless and doesn’t affect the look or feel of the material in any way. It is a permanent coating too, being bound to the material surface on an atomic scale.

Plasma coatings are one of the most exciting areas of plasma technology, offering enormous potential to enhance a material’s function and value over a wide range of applications. They deliver two main categories of surface property: totally liquid (water & oil) repellent, or totally wettable.

Hydrophilic Plasma Coatings

Hydrophilic plasma treatments render surfaces permanently wettable as shown below.

Plasma cleaning is a simple, fast and inherently clean alternative wafer preparation treatment. Oxygen plasma generates UV light together with reactive oxygen species which are extremely effective at the removal of both organic contamination and also complete PR layers. Both cleaning and PR removal are performed in the same equipment under the same conditions, with only the time of exposure to the oxygen plasma being varied.

How Plasma Coatings Work:

Monomers are introduced with the plasma feed gas. Monomers are small molecules which will, under the correct conditions, bond together to form polymers. Plasmas create the right conditions at the surface of the material for this to happen both quickly and efficiently. Different monomers are used to produce hydrophobic and hydrophilic surfaces.