Plasma Ruggedized Solutions (PRS) offers Parylene (XY) vacuum deposition services. Parylene is a polymer created from a chemical compound known as dimer \ ‘dî-mər\. The dimer is formed by the combination of two molecules of a single chemical compound. Parylene is considered one of the best conformal coatings available. The vapor deposition polymerization process allows Parylene coatings to be completely uniform in thickness and pin hole free. Parylene is truly conformal. Parylene is used in the medical, electronics, aerospace, automotive and military industries.
Parylene History
Parylene is the generic name for poly-para-xylylene, a polymer used as a conformal coating application. It was discovered in 1947 by a physical chemist named Michael Mojzesz Szwarc at the Manchester University in England. His discovery encouraged additional research by Union Carbide Corporation, where William Franklin Gorham established the process using a dimer (di-para-xylylene) to produce parylene. However, it was not until Donald Cram created a way to manufacture the dimer at UCLA (University of California, Los Angeles) in 1951 that the commercialization of parylene became possible. The most commonly used dimers are C, N and D. Most recently parylene HT (High Temperature) was added to the list. Although they all have the same coating properties, and are applied in the same manner, each has a unique molecular form which results in specialized performance and uniqueness.
Parylene C is the most widely used dimer; it provides a useful permutation of properties, plus a very low permeability to moisture, chemicals and other corrosive gases.
Parylene N provides high dielectric strength and dielectric consistency which does not vary with changes in frequency. Optimum alternative, if superior coating shield is required. Due to the greater molecular activity at the monomer stage parylene N offers the highest penetrating power.
Parylene D keeps its physical strength and electrical properties at higher temperatures.
*Parylene C and N are most commonly used in the medical industry. Need additional technical specifications? Email us at: sales@plasmarugged.com
Parylene Facts
Parylene is a polymer created from a chemical compound knows as dimer \ ‘dî-mər\, which is in a powder form. The dimer is formed by the combination of two molecules of a single chemical compound, used in the polymer deposition process. When heated, it is transformed into a gaseous state monomer \ˈmä-nə-mər\. The monomer is a chemical compound which undergoes polymerization. At this stage, the vacuum pump extracts the gas into the deposition chamber where it polymerized and develops a film, which is deposited evenly on any available surface. The gaseous nature of the deposition process allows parylene to penetrate and coat surfaces that are unreachable by liquid coatings, including sharp edges, and deep cavities.
Parylene provides exceptional dielectric strength, and resistivity. These electrical properties are essentially independent of temperature. It provides a conformal, pinhole-free coating that is corrosion resistant. The uniqueness of these properties and consistency makes parylene the first choice of protective coatings for extreme or challenging environments in the medical, automotive, defense, aerospace and aviation industries.
The Parylene Process
Subsequent to suitable cleaning and masking, the commodities to be coated are positioned in the deposition chamber. The product remains at room temperature during the coating process. (The dimer is then added). Coating thickness is controlled by the amount of dimer loaded into the system.
Vaporization Phase: The parylene dimer is heated (di-para-xylylene) until it changes from solid to vapor state.
Pyrolysis Phase: Dimer molecules are heated to 680C, 0.5 torr. pyrolysis (para-xylylene) zone. The high temperature cleaves the dimer into two monomers.
Deposition Phase: Monomer molecules enter the deposition chamber and form the polymer (poly-para-xylylene). The coating forms consistently over all available surfaces.
