technical information on Parylene

What is parylene?

Frequently asked questions.

parylene atomic structure

Parylene is a common generic name for a unique series of polymers based on paraxylene. The three most common types of Parylene are Parylene C, Parylene N, & Parylene D.

In actual usage, Parylene C is by far the predominant type used for most types of applications and as such is usually the kind of material associated with the name "Parylene." The basis for the parylene family is the polyp-xylene monomer which comprises Parylene N. Parylene C & D are created by the substitution of a single chlorine molecule (C) or two (double) chlorine molecules (D).

Parylene C

The most widely used providing a useful combination of properties, plus a very low permeability to moisture, chemicals, and corrosive gasses.

parylene-c

 

Parylene N

Provides high dielectric strength and a dielectric constant that does not vary with changes in frequency. Best selection where greater coating protection is required.

 parylene-n

 

Parylene D

Maintains its physical strength and electrical properties at higher temperatures.

parylene-d

 

pyrolysis of a di-p-xylene dimer

The Parylenes are formed by the pyrolysis of a di-p-xylene (dimer) in a vacuum environment which is then deposited on a cooler (i.e. room temperature) substrate while under continuous vacuum.

Vapor phase deposition of the parylene polymer allows it to be formed as a structurally continuous film which is truly conformal to the design and structure of the substrate upon which it is being deposited.

Parylene can be effectively deposited with excellent accuracy in thickness over a range from 0.2 µm (microns) to well over 2 mils.