Parylene is ideal for medical applications requiring a protective conformal coating, biomedical compatibility and deposition to a thickness that is both critical and consistent.
Parylene provides a pin-hole free protective barrier against biofluids, moisture and chemicals.
Parylene also acts as a dry film lubricant with a coefficient of friction measurement that approaches that of TEFLON®. Parylene type N is typically used in applications requiring this type of releasability or dry film lubricant.
Typical medical applications include:
- STENTS – uniquely suited to coat the intricate structures of stents, without webbing or pooling. Parylene is nonthrombogenic and can facilitate the adhesion of drug-polymer combinations when applied directly onto Parylene coated stents.
- CATHETERS – improved lubricity, reducing the chatter of insertion or removal and barrier protection against biofluids.
- MANDRELS – to increase the releasability of the newly formed catheter from the forming mandrel.
- CARDIAC ASSISTED IMPLANTABLE DEVICES – protection for pacemakers and implantable defibrillators against the corrosive effects of biofluids including the electrical isolation of metal cases.
Other applications include pressure sensors, medical instrumentation, ultrasound transducers, guide wires, needles, epidural probes and elastomer products (silicone, latex gasket and seals), wherever lubricity and barrier protection is required.
Parylene films ranging from 6 µm – 40 µm in thickness provide a barrier which is equivalent or superior to 50 µm – 150 µm of other conventional coatings. Parylene does not pull away from edges or exhibit meniscus forces as do conventional liquid coatings applied by spraying, dipping or brushing. Board components are evenly and consistently coated with an ultra thin layer of Parylene. The dielectric constant and dissipation factor are practically insensitive to changes in frequency.
Given its resistance to humidity, its barrier, physical and thermal properties and its unique molecular structure, Parylene is practically insoluble in all known organic and inorganic solvents including strong acids and alkali. Parylene has proven to be an effective barrier against corrosive agents and does not out-gas. Parylene is an excellent choice when it comes to conformally coating printed circuit boards for military and aerospace applications.
When looking at the total cost of protecting electronic components in a hazardous or contaminated environment, Parylene provides an extremely cost effective option.
WIRE WOUND DEVICES
- wire wound ferrite cores
- powdered ferrite cores
Parylene eliminates abrasion damage to the wire in the winding process along with uniform coating thickness. Unlike the variance of thickness (bridging, shrinking, thin out and pin-holes) with conventional liquid, spray or brushed on coatings, Parylene gives a maximum winding window.
Parylene does not impart magnetostrictive or permeability problems that may be encountered with conventional varnish impregnation.
With Parylene's low water vapour transmission properties it provides excellent corrosion protection.
Parylene yields a truly conformally coated part with a consistent thickness on the flat surface area and around the internal dimensions of holes. Irrespective of the size or shape of the elastomer application, Parylene film conforms to the surface features.
With Parylene film's surface adhesion and elasticity, the coating can handle substantial elongation of the elastomer part with minimal fracturing or breaking of the surface adhesion of the film from the substrate bond.
Rubber keyboard applications using the Parylene coating process will remove the elastomer tack but will also protect the keyboard against dirt, oils, petrochemicals and solvents whilst also protecting printed legends from wear.
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