When it comes to conformal coating, you have a variety of options depending on the scope and needs of your specific project. However, two choices often prove to be superior no matter the application: parylene and Teflon. Here's what to know about each coating type and how they compare.
Comparing Parylene and Teflon
Conformal coatings like parylene and Teflon are designed to increase consumer product lifespan, ensure proper performance of electronics, protect against extreme environments, and more. They have found homes in a variety of endeavors, from aerospace travel to medical equipment, and continue to be a vital choice in many projects.
However, parylene and Teflon are not interchangeable. It's important to understand the differences between these two coating types before choosing one for your needs.
Parylene was discovered in 1947, when Michael Szwarc performed thermal decomposition of p-xylene at high temperatures. The result was a polymer that would go on to change the world in significant ways. Other researchers contributed to these changes by identifying different parylene types and production methods, even creating 20 different types of this polymer. However, only three remain relevant today: Parylene C, Parylene D, and Parylene N (though Parylene F is used on rare occasions).
Each type has its own properties, but in general, parylene acts as a thin, pinhole-free coating capable of adhering to unusually shaped and sized substrate surfaces. Parylene is also highly reliable, providing protection against:
- Temperature extremes.
- Corrosive gases.
Parylene advantages include:
- Even deposition: Because parylene is applied in a gaseous form, it can easily and effectively provide an even coating to surfaces with crevices, angles, or irregularities. The resulting coat will not lift at the edges or create ridges, leading to a smooth, reliable finish.
- High stability: Parylene is inert and resistant to temperature extremes, making it a highly stable choice for many applications. It can also be sterilized without breaking down or otherwise jeopardizing its structure.
- Bio-compatibility: Parylene has a bio-compatible structure, which means it will not interact negatively with the body when used for medical devices.
- Transparency: When applied properly, parylene coating is clear and does not absorb visible light. The result is a transparent but protected surface.
- Simplicity: Despite its original creation occurring in high temperatures, modern parylene is applied at room temperature. This removes one variable--temperature extremes--from the application process and protects substrate surfaces from thermal stress. Parylene also doesn't require conventional curing, meaning there is no mechanical or temperature stress during this process.
- Environmental friendliness: Other coating types create high levels of gaseous byproducts and contain high VOCs. Parylene is a comparatively green choice.
Teflon is the commercial name for polytetrafluoroethylene (PTFE). It was discovered by Dr. Roy J. Plunkett through experimentation with tetrafluoroethylene (TFE). Further tests indicated that the substance couldn't be polymerized and was highly stable, and other researchers contributed to additional studies to determine more characteristics. Ultimately, PTFE was registered as Teflon in 1945.
Like parylene, Teflon has many uses and can protect against a variety of extreme environments. For example, its high melting point makes it a particularly effective choice for high-temperature applications--and this, combined with its slippery surface, is why Teflon is a popular coating for non-stick pots and pans.
Teflon has many other things in common with parylene, like its high conductivity characteristics and chemical resistance. It's also used in some of the same industries, like aerospace. However, unlike parylene, the coating process is not ideal for many applications, interfering with the structure or performance of certain substrates; furthermore, the coating can produce particulates that impede project reliability, especially in medical applications.
Parylene or Teflon: Which is Right for Your Project?
While parylene and Teflon both have their advantages, it's vital to choose the coating type that aligns with your project needs, substrate surface type, and ultimate goals. Here are a few things to consider:
- Characteristics: Teflon and parylene are similar in many ways, but each has its own unique melting point and other characteristics. Carefully review these before selecting a coating type.
- Application process: The application process for parylene is generally considered simpler and less stressful for electrical, mechanical, and other sensitive substrate components. Teflon's application, meanwhile, can interrupt performance, making it less than ideal for some projects.
- Reliability: Parylene has an impressive lifespan and provides thin, pinhole-free coverage. Teflon matches this in many regards but fails to be completely reliable because of its tendency to create particulates.
In the world of conformal coatings, parylene and Teflon are often frontrunners. However, these coating types aren't interchangeable, and choosing the right one for your project requires an in-depth review of each option. In most cases, parylene is likely to come out on top.
Contact us today to learn more about parylene coating and whether it's right for your application project.