Parylene is a polymer that cannot be applied by brush, dipping, or spraying. It forms directly on the part to be protected, molecule by molecule, from a vapor. This process, developed by William Gorham in the 1960s, takes place under vacuum and consists of three successive steps, each in a separate zone of the machine. Parylene is deposited by a three-step CVD (Chemical Vapour Deposition) process carried out under vacuum. This unique process, solvent-free, catalyst-free, at room temperature allows it to uniformly coat all surfaces, including complex 3D geometries, cavities, and sub-surfaces.
The parylene coating process is a three-stage vacuum CVD process. Each stage has distinct thermodynamic and kinetic characteristics.
Everything starts with the dimer, a white crystalline powder of a di-molecule of parylene.
This powder is placed in a furnace called the vaporizer, heated to about 120–170 °C under vacuum. At this temperature, the dimer does not melt: it sublimes, meaning it goes directly from solid to gas, like dry ice.
The result is a dimer vapor, still chemically stable and non-reactive.
The dimer vapor then passes through a tube heated to a very high temperature, around 650–690 °C: the pyrolysis oven.
The thermal energy is high enough to break the two carbon-carbon bonds that hold the two halves of the dimer together. Each dimer molecule splits into two identical monomers.
This monomer is an extremely reactive intermediate: all it wants to do is bond with other monomers to form long polymer chains.
The gaseous monomer finally reaches the deposition chamber, kept at room temperature (about 25 °C) and under a vacuum.
On contact with the cold surfaces, the monomers condense and polymerize spontaneously: they link together into polymer chains, forming a solid film of parylene.
This is where the real strength of the process lies. Since the monomer is a gas that moves freely, it reaches everywhere: into cavities, under components, into gaps only a few micrometers wide.
The film therefore grows perfectly conformally, with a uniform thickness on every surface of the part, even the most complex geometries.
The vapor-phase surface polymerization requires no solvent, no initiator, no catalyst, and occurs at room temperature on the substrate. It is suitable for the most sensitive components: electronics, sensors, implantable medical devices. The resulting film is exceptionally pure (>99.9wt%), defect-free, and grows simultaneously on all exposed surfaces regardless of geometry, including re-entrant features, capillary gaps, and the undersides of components, a conformality that no liquid-applied coating can replicate.
Lorem ipsum dolor sit amet congue sollicitudin erat integer pharetra nec duis tortor hendrerit. Pulvinar malesuada arcu ultrices venenatis suspendisse sapien facilisis. Gravida nisl quisque risus donec leo purus consequat erat a massa enim. Donec etiam suspendisse sagittis tellus lectus nisi id odio netus aenean urna morbi. Dictum in hendrerit tincidunt ultrices libero eros lacinia tempor gravida sollicitudin lacinia sodales blandit.
