Parylene Coating Blog by Diamond-MT

Where to Buy Parylene

Posted by Sean Horn on Fri, Jul 28, 2017 @ 07:38 AM

Materially, parylene is the most distinctive of the major conformal coatings.  But just how does it differ from liquid coatings -- acrylic, epoxy, silicone and urethane??  

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Tags: parylene, parylene deposition, parylene dimer

Lubricious Coatings

Posted by Sean Horn on Fri, Jul 14, 2017 @ 07:37 AM

Contributing to good performance for internal medical appliances, lubricity is a conformal coating’s ability to lower operational friction that might retard its function and endanger patient health.  Lubricious coatings offer essential protection for appliances like cardiac-assist devices (CADs), catheters, elastomers, guidewires, and stents.  Compared to an uncoated device, lubricious films can reduce frictional forces by more than 90%, dramatically decreasing potential harm caused by excessive insertion-force or internal puncture damage.  This relative ease of use is important for implants and similar devices that require navigation throughout the patient’s vascular system or other internal structure; otherwise, patients can suffer from abrasion generated between the device surface and blood vessel walls. 

Coefficient of Surface Friction

The degree of physical resistance a device demonstrates is numerically expressed by a coating’s coefficient of friction (µ), which quantifies:

Static friction (µs) occurs when an object moves across a stationary surface; kinetic friction (µk) results for two objects simultaneously in motion, moving across each other.  Conformal coatings are used in both circumstances, especially for medical implants with moving MEMS/nano-tech components.

Where higher-level surface lubricity is sought, lower µ-values are the objective; they signify lessened frictional resistance, minimizing non-release, dry-sticking challenges that interfere with devices’ performance.  For instance, a µ-value of 1 indicates an equal quantity of force is needed to either lift an object, or slide it across a level surface; these calculations compare an object’s weight to the total force required to make it move.  Most everyday objects and materials have a coefficient between 0 and 1; values closer to 1 are not feasible for medical purposes.  For medical devices, a µ-value:

  • ranging from 0.01 to 0.1 is ideal,
  • but remains difficult to achieve
  • for application to the expansive degree of metallic and polymeric substrates used for medical appliances,
  • which require highly-specified levels of abrasion resistance and non-thrombogenic properties,
  • in addition to biocompatibility and lubricity.

Appropriate safety standards also need to be met.

Much depends on the materials comprising the touching surfaces.  Conformal coatings like Teflon (PTFE) and parylene, which provide high-level lubricity, maintain that level for a prolonged operational duration, making them very useful for specialized medical applications.

Properties of Reliable Coating Lubricity

Lubricated surfaces have lower levels of friction.  Wet hydrophilic coatings amass water as a source of lubricity, applied by liquid methods such as dipping or spraying the film substance onto substrates.  Applied to catheters or guidewires, they temporarily minimize development of thrombosis.  However, their lubricious function decreases with time, dissociating or dissolving from the matrix surface, leaving particulates in tissue or the bloodstream, endangering patient health.  Thus, they are less reliable long-term than hydrophobic coatings   

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Tags: parylene, parylene properties, Medical conformal coatings, medical device coating, lubricious coatings

Solvent Use in Parylene Deposition

Posted by Sean Horn on Fri, May 26, 2017 @ 07:32 AM

For various reasons, even people familiar with the variety of existing conformal coatings, their strengths, weaknesses and respective use often assume that the chemical vapor deposition (CVD) process used for parylene films incorporates a solvent, as an integral component of the procedure.  This is false, for the reasons detailed below.

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Tags: parylene, parylene process, conformal coating solvents, solvents

Which Conformal Coating Is Right for Me?

Posted by Sean Horn on Fri, May 19, 2017 @ 07:30 AM

          The value of polymeric conformal coatings for protecting printed circuit boards (PCBs) from functional retardants like dust, corrosion, moisture, and temperature fluctuations has been well-documented.  Conforming to the physical configurations of the exposed face of the PCB, conformal coating:

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Tags: acrylic conformal coating, parylene, conformal coating, silicone conformal coating, urethane conformal coating

Solvent Resistance of Parylene

Posted by Sean Horn on Fri, May 12, 2017 @ 07:25 AM

The parylene variants are resistant to solvents and protect substrates solvents.  This high level of security is maintained through temperatures of 150° C, seldom encountered in the actual use of PCBs or related electronics.  These properties are largely a development of the unique molecular structure of parylene polymers, rendering them:

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Tags: parylene, parylene properties, conformal coating solvents, solvents

Ruggedizing UAV Electronics with Parylene

Posted by Sean Horn on Fri, May 05, 2017 @ 07:37 AM

The acronym UAV stands for an unmanned aerial vehicle, an aircraft piloted by remote control or onboard computers.  UAVs are an integral element of America’s unmanned aircraft system (UAS), consisting of three basic components:

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Tags: parylene, rugged electronics, COTS, ruggedization, military electronics

Protecting Solar Panel Electronics with Parylene

Posted by Sean Horn on Fri, Apr 28, 2017 @ 07:36 AM

Like any other renewable energy technology, electronics for solar (photovoltaic) panels are necessary for transforming, transmitting, and monitoring the system.  Unfortunately, system electronics can be fragile, and frequently are the panel’s weakest link.  Converting the sun’s light to electricity, solar panels have demonstrated their utility in numerous operational contexts.  The basic operational unit of panels, the solar cells themselves, can be used to power small scale products like calculators, re-chargeable batteries or watches; full panels can be adapted to a range of larger level operations, like powering homes, lighting systems or water treatment plants.

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Tags: parylene, parylene applications, parylene solar panels

Repairing Parylene Delamination

Posted by Sean Horn on Fri, Apr 21, 2017 @ 07:37 AM

Applied as a conformal coating through a unique chemical vapor deposition (CVD) process, parylene provides micron-thin, resilient barrier protection for an exceptional range of electrical assemblies.  In comparison to liquid coatings -- acrylic, epoxy, silicon, urethane -- parylene is the coating-of-choice for protecting printed circuits boards (PCBs) and medical devices.  It’s films negate the impact of gravity and surface tension during the coating process; . 

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Tags: parylene, parylene adhesion, parylene disadvantages, parylene delamination, parylene issues

Batch Size Considerations for Parylene Production

Posted by Sean Horn on Fri, Apr 14, 2017 @ 07:35 AM

The parylenes consist of a range of para-xylylene polymers whose desirable physical and electrical properties support expansive utilization as conformal coatings for electronic and medical devices  Parylene films are applied to substrates via a chemical vapor deposition (CVD) process, which deposits monomeric parylene vapor homogeneously and deeply into the surface of printed circuit boards (PCBs) and related assemblies/components. 

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Tags: parylene, parylene process, parylene deposition, parylene disadvantages

Cost of Parylene Dimer

Posted by Sean Horn on Fri, Apr 07, 2017 @ 07:32 AM

Perhaps the most reliable of the conformal coatings, parylene (para-xylylene di-iodide) is also one of the more expensive coating options.  Production costs typically encompass three primary expense categories -- raw materials, labor, and lot volume.  Of the three, labor expenses are generally the most costly, but raw materials can add significantly to production overhead; materials’ costs can be largely attributed to the raw parylene dimer required to make conformal coatings.   

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Tags: parylene, parylene dimer, parylene C, parylene n, parylene af-4