Parylene vs. Teflon Coating

Whether you’re manufacturing electronics or medical equipment, the coating you use can make all the difference. Parylene and Teflon are versatile conformal coatings used in many of today’s industrial and commercial industries. Both are used to enhance strength, function, and increase the life cycles of everyday products while providing protection from rust and corrosion. While the two types of coatings have proven protective qualities, they are used for different applications and purposes. To better understand and compare the two coatings, it pays to take a look back at their history as well as the ways they’re used today. Let’s dive in.

The Discovery of Parylene

Parylene, or poly paraxyxylene, was discovered by British chemist Michael Szwarc in 1947 as he was conducting experiments on chemical bonds between carbon and benzene rings. Szwarc produced the polymer through the thermal decomposition of p-xylene at a temperature of 700-900 degrees Celsius. He confirmed the product as para-xylylene by reacting the vapors with iodine. Szwarc’s observations inspired further research by DuPont, Kellogg, and Polaroid.

William F. Gorham at Union Carbide found a more efficient route to produce the polymer in a way that reduced the gaseous by-products. In February of 1965, the new polymeric coating system was given the title of Parylene. Union Carbide continued to produce 20 types of Parylene, but only three were deemed commercially viable.

Features and Uses of Parylene

Today, Parylene is used in virtually every global industry and is considered to be the ultimate coating for the protection of devices, components, and surfaces in electronics, instrumentation, aerospace, and engineering industries. Parylene’s ultra-thin lightweight film provides pinhole-free protection against the effects of fluids and solvents. For an in-depth look at how it works, you can download VSi Parylene’s Complete Guide to Parylene Coatings.
With its bio-compatible composition, Parylene is most widely used in the medical sector. Typical products coated with Parylene include coronary stents, probes, needles, catheters, hearing aids, and medicine bottles.

Other benefits are as follows:

• High stability since it is inert and insoluble in most solvent systems within its temperature range.
• Extremely high dielectric strength of 7 kV/mil.
• Acts as a dry film lubricant, eliminating the need for liquid release agents.
• Provides protection from moisture, corrosive bodily fluids, chemicals, gases, temperature, and fungus.
• Sterilization has little impact on Parylene’s physical properties.
• Parylene is optically clear to allow markings under parylene to be seen.

Other popular uses of Parylene coating include:

• Military and defense parts
• Semiconductor products
• LEDs
• Corrosion protection for metallic surfaces.
• Microwave electronics.
• Wires and cables

Teflon’s Accidental Discovery

Teflon, the brand name for polytetrafluoroethylene (PTFE) was discovered by accident in 1938 when Dr. Roy J. Plunkett produced the substance with a sample of frozen, compressed tetrafluoroethylene (TFE). Thinking that the canister of TFE was malfunctioning, Dr. Plunkett cut it in half where he discovered a white flake, a polymer, had developed inside.

Dr. Plunkett ran further tests on the substance and found it was impossible to polymerize. It was also one of the most slippery substances ever encountered. PTFE was also discovered to be non-corrosive, chemically stable, and have a high melting point.

Further research was allocated to chemists at DuPont’s Central Research Department and was registered in 1945 under the Teflon trademark. The Chemours Company, a spin-off from DuPont, produces a family of Teflon fluoropolymers for various uses.

Benefits and Uses of Teflon

Teflon’s melting point is around 327 degrees Celsius and is almost totally chemically inert, highly insoluble in most solvents and chemicals, and has high flexural strength even at low temperatures. Teflon’s unique properties offer several other benefits, including the following:

• Excellent thermal and electrical insulation properties
• Low coefficient of friction
• FDA approved
• Chemical and high-heat resistant
• UL94-CO flame rating

While widely recognized as a non-stick coating for pots and pans, the coating’s chemical inertness and temperature resistance makes it ideal for use in industrial settings with harsh environments. As a liquid, Teflon’s lubricating properties make it an excellent choice to reduce friction and component wear in machines with sliding parts, gears, slide-plates, and other moving components. Teflon is used in the following industries:

• Oil and gas refineries and pipelines depend on Teflon’s high chemical and thermal resistance to chemicals
• Aerospace and aircraft industries use Teflon fluoropolymers for their resistance to hydraulic fluids and solvents, as well as for operation over extreme temperature ranges
• Teflon fluoropolymers are used in semiconductor manufacturing to increase corrosion resistance and prevent leaching
• Medical packaging and chemical processing rely on Teflon films for chemical and weather resistance

Key Takeaways

It’s true that Teflon and Parylene coatings are used in a variety of settings to protect products from heat, moisture, and chemical damage, and both can prolong the lifespan of components while adding only minimal weight. However, when comparing Teflon vs. Parylene side-by-side, Parylene comes out on top as the far better choice, providing substantial benefits for a wide variety of uses and industries. It shines in medical settings, as it protects both patients and providers from bacterial contamination. Plus, its unique properties make it the ideal coating for electronics manufacturers around the globe.

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