Transparent Amorphous Fluoropolymer Coatings Protect Sensitive Electronics and Optics Components and Transmit Light

Fluoropolymer coatings for electronic components.

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Components inside devices can corrode when exposed to contaminants and moisture. This corrosion can reduce electronic performance and cause electrical shorts and device failure. Manufacturers use specialized coatings to protect these sensitive components.

Factors to consider when selecting coating materials for electronics are the service environment, the component’s life span and the cost of the coating.

There are a wide range of coating options. However, many of them are not suited for optical products and other electronics that require full light to function optimally. Optics especially require coatings that are both protective and allow maximum light transmission. This ensures better image sharpness and contrast

AF Polymer Coatings Perform Like Transparent PTFEs

Conventional fluoropolymers, like PTFE (polytetrafluoroethylene) resins, impart strength, durability, heat and chemical resistance and high-performance electrical insulation. These characteristics help extend the lifespan of components and improve their fire safety. However, they are not transparent.

AGC’s development of transparent amorphous fluoropolymers (called CYTOP™) provides new options for many industries, especially electronics and optics. They can withstand harsh environmental conditions, so are ideal for coating electronic components, such as circuit boards.

Its amorphous structure is completely different from other fluoropolymers. It is a unique molecular structure comprised of non-crystalline fluoropolymer particles dispersed in a special fluorinated solvent.

CYTOP coatings have all the performance advantages of PTFE, but they are transparent, with a visible light transmission ratio of more than 95%. This enables manufacturers to make thin film coatings that generate anti-reflective properties over optical components for eyeglasses, photo masks and optical fiber, for example.

Most fluoropolymers are insoluble, so they need to undergo a baking process to adhere them onto the substrate. CYTOP eliminates this process. CYTOP has a high solubility rate and can be dissolved in a special fluorocarbon solvent. This makes it easy to coat it onto a substrate and enables users to customize the thickness of the coating depending on the amount of solvent used. CYTOP can be used in thin film coatings to a thickness of a few sub-microns.

CYTOP fluoropolymers can be used to coat a wide variety of applications including:

  • Optical fibers
  • Graded-index optical fibers
  • Inter-level dielectric layer for semiconductors
  • Pellicles
  • Protective coating for semiconductors
  • Non-autofluorescence hydrophobic coating of microfluidics
  • Hydrophobic coating of Electrowetting devices
  • Antifouling coatings for photomasks
  • Optical film
  • Anti-reflective displays
  • Insulation materials for displays

Types of CYTOP

CYTOP is available in three types that are suited for different applications. Each has a unique functional group at both ends of the polymer.

Type A

Metal and glass are coated using a silane coupling agent together with this type of CYTOP. Type A is used with a special primer to coat plastics. It is transparent to visible light, so is ideal for use on anti-reflection film and optical membranes. It also works as a water and oil repellent and an electric insulator.

Type M

This type is used in one-step coating processes for metals and glass. It is used as a protective layer, a water and oil repellent or an electric insulator.

Type S

This type exhibits a high transparency for a wide range of light, from visible to ultraviolet (UV). It also imparts a very tough UV resistance as well as resistance to adhesion. This type is ideal for coating pellicles and optical materials, and can be used to facilitate mold release.

Coating methods

CYTOP coating techniques depend on the base material, shape, and expected thickness of the coating. Three methods that can be used are:

  • Spin-coating to coat flat and circular boards.
  • Dip-coating used to coat any type of board.
  • Potting method to coat any type of board.

For more information assistance in selecting the right CYTOP transparent amorphous fluoropolymers for your specific application, please visit or call 800-424-7833.


AGC Chemicals