Parylene Uses

Parylene coating has been commercially available for over 30 years and its properties are exploited in a wide range of applications.

Circuit Boards
Coatings are thin, truly conformal, stress-free and resistant to solvent and fungal attack. Good adhesion minimises ionic conduction at the coating-substrate interface and strengthens solder joints. Low dielectric constant minimises loading in high frequency applications.
Circuit Boards
Hybrid Circuits
Good adhesion to ceramic substrates. Good throwing power enables coating within spaces as narrow as 10μ. Interior of packages may be coated via a 1mm hole - coating strengthens wire-bonds and immobilises particles of debris such as solder balls.
Hybrid Circuits
Components
Ferrite cores and bobbins are coated to reduce friction and abrasion in coil forming and to prevent chipping and dust formation. Coating cast metal magnets gives corrosion protection and electrical insulation. Accelerometers, strain gauges, pressure sensors etc may be coated for electrical insulation and environmental protection.
Components
Rubber and Plastics
In the coating process the monomer is able to penetrate the surface of rubbers and plastics giving very good adhesion. A 2μ coating imparts dry lubricant and wear resistance characteristics to the surface. For example silicone rubber keypads are coated to improve the 'feel' of the surface and to protect the printing and 'O'-rings are coated to reduce friction in, for example, syringes. A thicker coating improves chemical and solvent resistance.
Rubber and Plastics

Medical Components
Because Parylene has excellent barrier properties, cannot be hydrolytically degraded in the corrosive biological environment and is capable of penetrating and coating the bore of narrow tubes it has many uses in this field:

    • Protecting electronic circuitry and other components for example in pacemakers
    • Protecting the body from toxic materials
    • Adding surface lubricity to improve the functioning of catheters, probes, etc
    • Trapping and preventing the production of surface debris in, for example, implants

Optics & Instrumentation
The excellent optical and barrier properties of Parylene and the stress-free nature of the coatings find many uses in this field, particularly in protecting moisture-sensitive elements such as potassium bromide windows. Freestanding films of Parylene may be produced by stripping the coating from suitably prepared glass plates and are used to produce windows and other components in instrumentation.

The unique application process and the predictable barrier properties and mechanical strength of Parylene coatings have also found other interesting applications:

  • Strengthening paper in old books and manuscripts — books may be coated without dismantling them
  • Preserving archaeological artefacts particularly those from underwater sites such as the Titanic
  • Coating explosives and solid rocket fuels to make them less moisture sensitive and to modify other characteristics.

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