The poly para xylylene, commonly known as parylene, refers to specific polymers belonging to a unique chemical family used to provide protective coatings. The subject undergoes a robust coating process to deposit the parylene through vacuum deposition.
This coating type provides excellent protection as it is chemically inert and physically stable when used at the appropriate temperature. Here, you will learn common parylene features and how they are applied in different fields. See more to learn about parylene.
How Is Parylene Deposited?
The entire process is called vapor deposition polymerization and occurs in an enclosed vacuum chamber at room temperature. The process starts by using a vaporizer to heat a powderly material referred to as a dimer. The vapor is then subjected to a high temperature that makes it lose the structure into a single molecule vapor.
This way, the vapor is transformed into a deposition compartment and easily polymerizes onto the substrate and forms the parylene coat. Notably, the vapor successfully covers every part of the complex structures thanks to its monomeric nature.
Different Types of Parylene
Parylene C: This parylene contains two chlorine atoms that replace those of hydrogen. It is also a carbon-hydrogen combination making it highly moisture resistant.
Parylene D: Like type C, this type also has a replacement of two hydrogen atoms with chlorine enabling it to withstand extreme temperatures. However, it lacks sufficient biocompatibility to be used in medical devices.
Parylene HT: This type has fluorine atoms replacing hydrogen atoms and is ultraviolet (UV) stable. It offers the strongest coating due to its small molecule size.
Parylene N: This type has a linear molecular structure, with each molecule containing a carbon-hydrogen combination.
Parylene’s unique molecular structure makes it practically insoluble and highly resistant to common reagents, including alkali and acids. This feature enables the chemical to create effective barriers against corrosive agents.
Incredible Mechanical Strength
It is the reason parylene is used to encapsulate microcircuits as it enhances wire and lead bonds, conductor bridges, and face bonded chips contributing to their integrity. The chemical’s low gravity also makes the coating lighter than other applicable coatings.
Parylene has superior electrical properties to other conventional coatings. Notably, increased frequency in the substrate does not affect its dissipation factor and the dielectric constant.
So, What Are The Common Uses?
Electricals and Electronics
Parylene is one of the successful coatings used in electrical and electronic applications, including microelectronics, rotors, microelectronics, circuit boards, semiconductors, switches, computer keypads, and disk drives. Other notable applications are in space and nuclear energy equipment.
These are the Microelectromechanical Systems that provide a high-level integration of molecular detection, computation, sound, light, motion, and radio waves. Normally, the parylene coating has provided this protection for years as the systems converge on a tiny chip array and have various uses which require an effective coating to prevent damage or interference.
Parylene provided protective coating on biomedical surfaces to isolate substances and chemicals that may affect their performance and durability. Parylene is the most preferred coating as it withstands high electric fields, is thin, nontoxic and sterilizable.
As you have seen, Parylene has numerous uses due to its suitable features. The different types offer different protection making the chemical common in different fields.