Parylene

Parylene is the tradename for a variety of polyxylylene polymers marketed by several providers, including Kisco Conformal Coating, LLC [cite web | url = http://http://www.uniglobe-kisco.com/dix_introduction.htm | title = Introduction to Parylene | publisher = Uniglobe Kisco, Inc. | accessdate = 2008-04-28] , Para Tech Coating, Inc. [cite web | url = http://www.parylene.com/technology/parylene-technology.html | title = Parylene Technology | publisher = Para Tech Coating, Inc. | accessdate = 2007-07-07] , Specialty Coating Systems, Inc. [cite web | url = http://www.scscoatings.com/parylene_knowledge/history.aspx| title = Parylene Knowledge| publisher = Specialty Coating Systems, Inc. | accessdate = 2007-11-25] , and others. Parylene N is a polymer manufactured from di-p-xylylene, a dimer synthesized from "p"-xylylene. Di-p-xylylene, more properly known as [cyclophane| [2.2] paracyclophane] , is made from p-xylylene in several steps involving bromination, amination and elimination. [OrgSynth | collvolume = 5 | collvolumepages = 883 | year = 1973 | prep = cv5p0883 | title = Tricyclo [8.2.2.24,7] hexadeca-4,6,10,12,13,15-hexaene | author = H. E. Winberg and F. S. Fawcett]

There are a number of derivatives and isomers of parylene, but only a few are used commercially, e.g., Parylene N, Parylene C and Parylene D. This article discusses the unsubstituted molecule, which produces Parylene N. Heating [2.2] paracyclophane in a partial vacuum gives rise to a diradical species [cite journal
title = Macro rings. XXXVI. Ring expansion, racemization, and isomer interconversions in the [2.2] paracyclophane system through a diradical intermediate
author = H. J. Reich, D. J. Cram
journal = Journal of the American Chemical SocietyEdition
volume = 91
issue = 13
pages = 3517–3526
year = 1969
doi = 10.1021/ja01041a016
] [*cite journal
title = Polymerization of para-xylylene derivatives (parylene polymerization). I. Deposition kinetics for parylene N and parylene C
author = P. Kramer, A. K. Sharma, E. E. Hennecke, H. Yasuda
journal = Journal of Polymer Science: Polymer Chemistry Edition
volume = 22
issue = 2
pages = 475–491
year = 2003
url =
doi = 10.1002/pol.1984.170220218
] which polymerizes when deposited on a surface. Until the "monomer" comes into contact with a surface it is in a gaseous phase and can access the entire exposed surface. It has a variety of uses. In electronics, chemical vapor deposition at low pressure onto circuit boards produces a thin, even conformal polymer coating. Parylene coating has very high electrical resistivity and resists moisture penetration. It is used as a dielectric in certain high-performance capacitors for precision measurement. It has uses in preserving archival paper.

Characteristics and advantages

* Hydrophobic, chemically resistant coating with good barrier for inorganic and organic media, strong acids, caustic solutions, gases and water vapour.
* Outstanding electrical isolation with high tension strain and low dielectric constant
* A biostable, biocompatible coating, FDA permission
* micropore and pin get-free starting from 0.2 µm layer thickness,
* Thin and transparent coating with high gap freedom of movement, suitably for complex arranged substrates also on edges.
* Coating without temperature load of the substrates, coating takes place at ambient temperature in the vacuum.
* Highly corrosion resistant.
* Completely homogeneous surface.
* Thermally stable up to 220 °C, mechanically stable from -200 °C to +150 °C.
* Low mechanical stresses.
* Resistant to friction.
* Very low permeability to gases.
* High electrical impedance.

Typical applications

* Dielectric coating (e.g. Cores/coils).
* Hydrophobic coating (e.g. biomedical hoses).
* Barrier layers (e.g. for filter, diaphragms, valves).
* Microwave electronics.
* Sensors in rough environment.
* Electronics for space travel and military.
* Corrosion protection for metallic surfaces.
* Reinforcement of micro-structures.
* Abrasion protection.
* Protection of plastic, rubber, etc. from harmful environmental conditions.
* Reduction of friction (e.g. For guiding catheters, also acupuncture needles).
* Dissolving deuterated polyethylene for making nuclear targets.

External links

* [http://www.uniglobe-kisco.com/dix_introduction.htm Introduction to Parylene]
* [http://www.scscoatings.com/parylene_knowledge/history.aspx Parylene History]
* [http://www.parylene.com/technology/specifications-properties.html Parylene Specifications and Properties]
* [http://www.vp-scientific.com/parylene_properties.htm Parylene Properties & Characteristics]

References


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  • Parylène — Général Nom IUPAC poly(p xylylène) Propriétés chimiques Formul …   Wikipédia en Français

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  • Parylene — Pa|ry|lene [ paryli:n; Kurzw. aus ↑ para (4) u. Xylylen ], das; s; Syn.: Poly(p xylylen): aus [2.2]Paracyclophan (↑ Cyclophan) herstellbarer temperaturbeständiger Kunststoff …   Universal-Lexikon

  • parylene — par·y·lene …   English syllables

  • parylene — ˈparəˌlēn noun ( s) Etymology: contraction of para xylene : any of several thermoplastic crystalline materials that are polymers of para xylene and are used especially as electrical insulation coating …   Useful english dictionary

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  • Poly(para-xylylen) — Parylene ist ein inertes, hydrophobes, optisch transparentes, biokompatibles, polymeres Beschichtungsmaterial mit einem weiten industriellen Anwendungsspektrum. Die Beschichtung wird im Vakuum durch Kondensation aus der Gasphase als porenfreier… …   Deutsch Wikipedia

  • Polyparaxylylen — Parylene ist ein inertes, hydrophobes, optisch transparentes, biokompatibles, polymeres Beschichtungsmaterial mit einem weiten industriellen Anwendungsspektrum. Die Beschichtung wird im Vakuum durch Kondensation aus der Gasphase als porenfreier… …   Deutsch Wikipedia

  • Conformal coating — material is applied to electronic circuitry to act as protection against moisture, dust, chemicals, and temperature extremes that, if uncoated (non protected), could result in damage or failure of the electronics to function. When electronics… …   Wikipedia


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