Hydrophilic Plasma Coatings

Hydrophilic plasma coatings are a sub-category of plasma surface functionalisation, 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 effect 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.

 

A metal sample with a water droplet on displaying its inherent water repellent properties A metal sample with a water droplet on after plasma treatment displaying its improved hydrophilic properties

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.

An illustrative example of a piece prior to plasma coatingsAn illustrative example of a piece during plasma coatings treatment processAn illustrative example of a piece after the plasma coatings treatment process, displaying its deposited layer and improved wettability

Plasma coating is suitable for:

  • general plastics and rubber
  • performance textiles
  • filtration media
  • metals, glass, ceramics and composites
  • medical plastics
  • consumer electronics plastics
  • automotive components
  • aerospace components