The science behind fluoropolymer coatings for protecting electronic circuit boards

Nexus1

Recently, fluoropolymer coatings are being used more often to protect printed circuit board assemblies. This is because they have very specialized properties that are very different to traditional conformal coatings and these properties are being utilized highly effectively.

To understand these properties you have to understand what a fluoropolymer coating is made of.

Typically, the coating is comprised of fluorocarbons and characterized by carbon-fluorine bonds.

The coating itself is not susceptible to Van der Waals forces (interfacial electrostatic bonds). Therefore, the surface energy of the fluoropolymer coating is extremely low.

This means that there is no adsorption of another coating or liquid on the surface of the fluoropolymer and the coating shows the familiar, hydrophobic, non-wetting characteristics with water and oil.

This non-wetting is one of many of the key properties making them so popular.

Nexus2

The surface energy of the fluoropolymer coating is extremely low. There is no adsorption of water on the surface of the fluoropolymer and the coating shows the familiar, hydrophobic, non-wetting characteristics.


So, what other properties do fluoropolymer coatings have that help protect circuit boards?

Generally, fluoropolymer materials have very specialized properties.

For electronics the five key properties that are driving the interest in fluoropolymer technology are:

  • Being highly hydrophobic (water repellent)
  • Being extremely thin whilst still providing protection
  • Having a high moisture barrier and corrosion resistance
  • Having a high chemical resistance
  • Having high dielectric properties

To really understand the benefits you have to look at the key difference compared to a conventional conformal coating.


The key reason for using a fluoropolymer coating in electronics: No masking required

First, consider a conformal coating applied at normal thicknesses of 25um or more.

The coating is a high insulation material. Therefore, it must not be applied to a connector or part that can be damaged or needs electrical conductivity.

Further, the conformal coating naturally has good mar resistance and it cannot be easily abraded. It is tough to the touch and not easily removed.

So, if it was applied to the wrong component it would ruin the connection.

On the reverse side, a fluoropolymer coating can be applied at 1-2um in thickness and can still show the same performance characteristics.

Further, it is also extremely soft and shows almost no mar resistance when rubbed or abraded.

This allows the fluoropolymer coating to be applied to all connectors without fear of damage as the coating is easily removed or scratched away and the electrical circuit is easily made when the mating parts are connected together.

This key parameter of not requiring masking combined with the hydrophobic nature of the material and its other key characteristics makes the fluoropolymer coatings highly desirable in protecting electronic circuit boards.


Need to find out more?

Go directly to our Nano-coating fluoropolymer section or contact us directly and we can help you.

If you are new to Nexus and our work on conformal coatings then a good place to go is our Start Here page or our free conformal coating eBook.

Advertisements

What sectors are fluoropolymer coatings used? 

I am regularly asked where fluoropolymer coatings are used? After all they are a relatively new coating type in the world of conformal coatings and printed circuit boards.

Well to be honest, fluorinated coatings are used in almost all industrial sectors.

They include:

  • Aviation
  • Aerospace
  • Defense
  • Automotive
  • Industrial
  • Oil & Gas
  • Electronics
  • Medical/Pharmaceutical
  • Optics
  • Telecommunications
  • White goods / Commercial

This list is limited and there are a lot more areas that they are used.

In terms of products that are actually coated right now in fluoropolymer coating materials there are many.

They include:

  • Circuit boards
  • Mobile phones
  • Tablets
  • Automotive parts (gears, rotors, pistons)
  • Commercial bake-ware
  • Glassware, labware
  • Machine parts/components
  • Printing equipment
  • Sintered metal parts
  • Catheters, guidewires
  • Fasteners
  • Screen (metal/synthetic)
  • Filter media (cloth, synthetic)
  • O-rings, gaskets, seals
  • Silicone rubber
  • Solenoid, springs, coils

What is really interesting is that these coatings are really advancing in technology and changing all the time. Companies are tailoring the coating technology to the problem.

They are a wonderful material waiting for a project or problem to solve.

They are also being used in new and different ways.

For example, we are now experimenting with depositing the fluorinated films by plasma coating. This actually makes the bonding stronger and improves the overall performance without significant cost.

Fluoropolymer nano coating repels water 600

Fluoropolymer coatings are also being used in new and different ways. They are being depositing by plasma coating. This actually makes the bonding stronger and improves the overall performance without significant cost.


Need to find out more?

For further information on fluoropolymer coating then contact us directly and we can help you.

If you are new to Nexus and our work on conformal coatings then a good place to go is our Start Here page or our free conformal coating eBook.