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How Is Parylene N Different From Other Parylene Variants?

Mar 30, 2026

Overview & Key Takeaways Parylene N is the base polymer in the Parylene family of conformal coatings. Unlike other variants, it contains no halogens or additional chemical groups...

Parylene vs Liquid Coatings: An Engineer’s Selection Guide

Mar 02, 2026

Overview & Key Takeaways This guide provides engineers with a practical, side-by-side comparison of Parylene coatings vs. traditional liquid conformal coatings to support informed..

HZO Celebrates Pi Day 2025

Mar 13, 2025

In honor of Pi Day 2025, the HZO Team in Morrisville, North Carolina, headquarters honored our beloved Raspberry Pi computer that has been running and displaying our demo video -..

An Overview of Our Parylene Coating Equipment

Sep 26, 2024

The development of our coating technology began in 2007. We've come a long way since, filing more than 200 patents and protecting millions of digital devices. Today, we want to..

Parylene C Biocompatibility: Properties, Safety, and Medical Use Cases

Sep 24, 2024

Overview & Key Takeaways Parylene C is biocompatible and meets USP Class VI and ISO 10993 standards — the two primary benchmarks for medical device materials. It is the most..

Parylene Coating Removal - Methods & Best Practices for Each

Sep 12, 2024

Parylene coatings present unique challenges when it comes to rework and removal. They often outperform other conformal coatings. Parylene has better barrier properties, uniform..

ADAS Design and Validation for the Real World - Automotive Coatings

Jun 15, 2023

Advanced driver assistance systems (ADAS) continue to expand in features and functionalities. Standard offerings may include adaptive cruise control, park assist, blind-spot..

Parylene Conformal Coatings - Parylene Conformality Explained

Jun 06, 2023

Parylene (p-polyxylylene) conformal coatings are unique due to their capacity to be polymerized and deposited by the chemical vapor deposition (CVD) method onto surfaces near room..

Parylene Masking - General Concepts Explained

Jan 28, 2022

Conformal coatings are an excellent way to increase the reliability of electronic components in harsh environments. However, this protection can be too much of a good thing..

What is Parylene Coating? Uses, Properties, and How to Choose It

Oct 21, 2021

Overview & Key Takeaways Parylene coating is a high-performance conformal coating used to protect electronics and other sensitive components from moisture, chemicals, corrosion,..

How Much Does Parylene Coating Cost? - All Things Considered

Oct 15, 2021

Parylene coatings are known for robust protection from liquids, corrosion, chemicals, and strong electrical activity at a fraction of the thickness of alternative coatings, such..

IoT - Coating Consistency is Key

Sep 25, 2020

IoT sensors aggregate and send data to IoT dashboards, simplifying critical, complex decisions quickly. One key area where this is particularly true is the utilization of sensor..

Parylene Thickness - Industry Benchmarks, Cost, Effect on Properties

Aug 18, 2020

In the world of protective coatings, Parylene is a standout. Its unique, beneficial properties make it a great choice. Many Parylene types have distinct properties, like Parylene..

Solving Weather & Water Challenges For Smart Farms

May 12, 2020

It’s a Small World, After All The world’s population is projected to reach 8.5 billion by 2030, an unprecedented increase approaching fast. This looming surge will compound our..

How Is Parylene N Different From Other Parylene Variants?

March 30, 2026 / by Ryan Moore posted in Parylene, Protection Capabilities, Coating Properties, Resources

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Overview & Key Takeaways

Parylene N is the base polymer in the Parylene family of conformal coatings. Unlike other variants, it contains no halogens or additional chemical groups. This structure results in excellent electrical performance, facilitates high chemical purity, and enables ultra-uniform coatings on complex geometries. While Parylene N offers key advantages in certain electronics and precision applications, other variants may provide better environmental protection depending on the application.

Halogen-free composition: composed of only carbon and hydrogen, achieving high chemical purity and stable electrical properties.
Low dielectric constant: exhibits a range from 2.65 to 2.56 (60 Hz to 2 THz), making Parylene N suitable for RF electronics, MEMS, and high-frequency circuits.
Exceptional conformality: vapor-phase deposition enables coating of complex geometries, microvias, and fine-pitch assemblies with highly uniform films.
Phenomenal crevice penetration: Parylene N provides superior “throwing distance” or “crevice penetration” to most other variants. This is enabled by its lower sticking coefficient. Parylene N can coat greater aspect ratios and travel farther through narrow openings, allowing coatings under shield cans and within tubes.
Tradeoff vs. other variants: Relative to Parylene C and other variants, Parylene N exhibits reduced moisture-barrier performance and decreased oxidative stability at elevated temperatures or under intense ultraviolet and ionizing radiation in oxygenated environments. Coating selection must align precisely with the application's environmental requirements.

Quick Answer

Parylene N differs from other Parylene variants primarily in its halogen-free chemistry, lower dielectric constant, and exceptional ability to penetrate complex geometries. Because it contains only carbon and hydrogen, Parylene N offers high chemical purity and excellent electrical performance while being free of halogens, making it particularly valuable in high-frequency electronics, MEMS devices, and applications requiring ultra-thin conformal coatings, that also mitigates the risks of corrosive gas formation when burned, and mitigates the risk of corrosive halogen radical formation when exposed to atomic oxygen in low earth orbit (LEO) and other challenging aerospace environments.

However, compared with Parylene C, D, or F, Parylene N generally provides higher moisture-barrier permeability and lower maximum temperature capability, which means it is not always the best option for harsh environmental protection, where very high temperatures and relative humidity are of the greatest concern Please note though, that when compared most conventional conformal coatings, Parylene N provides excellent moisture barrier performance.

Parylene N vs Other Parylene Variants

Comparison Overview

Parylene Variant	Key Advantage	Main Limitation	Typical Application
Parylene N	Lowest dielectric constant, halogen-free chemistry, excellent penetration	Weaker moisture barrier than C	RF electronics, MEMS, biomedical devices
Parylene C	Strong moisture and chemical barrier	Higher dielectric constant	General electronics protection
Parylene D	Higher thermal and barrier performance than C	Less commonly used; high sticking coefficient and deposition rate leads to more challenging (worse) coating uniformity	Industrial and high-reliability electronics
Parylene F (AF-4)	Very high temperature capability	Higher cost and specialized use	Aerospace and extreme environments

What is Parylene N?

Parylene N is the base polymer in the Parylene family, consisting of poly-para-xylylene without any halogen substitution. The coating forms via a vapor-phase deposition process, in which a paracyclophane dimer is sublimated, pyrolyzed into a reactive monomer, and polymerized directly on surfaces.

Unlike other variants, Parylene C contains one chlorine atom, Parylene D contains two chlorine atoms, and Parylene F contains four fluorine atoms per repeat unit. Because Parylene N is composed solely of carbon and hydrogen, it offers contains only carbon and hydrogen, it provides exceptional chemical purity and predictable electrical properties.

Molecular Structure Differences

Parylene N chemical structure.

The key difference between Parylene N and other variants lies in molecular substitution. Parylene N uses an unsubstituted aromatic ring, while other variants introduce halogen atoms to alter performance characteristics.

Halogen substitution changes several properties, including barrier performance, thermal stability, electrical properties, and chemical resistance.

Electrical Performance Advantages of Parylene N

One of the most important advantages of Parylene N is its low dielectric constant.

Typical Dielectric Constants (60 Hz)

Material	Dielectric Constant
Parylene N	~2.65
Parylene C	~3.15
Parylene F (VT4)	~3.1

Conformality and Penetration

Like all Parylene coatings, Parylene N is deposited through chemical vapor deposition (CVD), producing extremely uniform coatings that conform to complex surfaces.

Parylene N’s polymerization behavior allows it to penetrate extremely small features including microvias, fine-pitch electronics, MEMS structures, and narrow gaps. This feature is known by different names across industries, including “crevice penetration,” “penetration depth,” “throwing distance,” “gap fill,” etc.

Chemical Purity and Halogen-Free Benefits

Because Parylene N contains no chlorine or fluorine atoms, it is considered halogen-free. This characteristic is valuable in applications where chemical purity is critical.

Moisture Barrier Comparison

While Parylene N excels in electrical performance, it is generally not the best Parylene variant for moisture protection. Parylene C is widely recognized for its superior moisture barrier properties. In applications where the presence of halogens may be an issue, Parylene N still offers a good moisture barrier, but may require a greater thickness than that of Parylene C to provide a similar level of moisture protection.

Thermal Performance

Halogen substitution also affects thermal behavior. Parylene N provides moderate thermal stability, while fluorinated Parylene variants offer much higher temperature capability.

When Should You Choose Parylene N?

hzo-engineer-examining-circtuit-board

Parylene N is typically selected when applications require low dielectric constant, stable electrical performance, halogen-free materials, ultra-conformal coatings, high chemical purity, and high lubricity.

When Is Parylene C a Better Choice?

Parylene C is often preferred when moisture protection is critical, chemical barrier performance is needed, or general environmental protection of electronics is required.

COMPARE PARYLENE VARIANTS WITH OUR DATA SHEET

Key Takeaways

Parylene N offers halogen-free chemistry, excellent dielectric performance, and superior penetration into complex geometries. However, it generally provides lower moisture barrier performance than Parylene C.

FAQ

Is Parylene N halogen-free? Yes. Parylene N contains only carbon and hydrogen atoms.
Does Parylene N have the lowest dielectric constant? Yes, among commonly used Parylene coatings.
Is Parylene N better than Parylene C? Not necessarily. Parylene N offers better electrical performance while Parylene C offers stronger moisture barrier protection.

Parylene vs Liquid Coatings: An Engineer’s Selection Guide

March 2, 2026 / by Ryan Moore posted in Parylene, Protection Capabilities, Coating Process, Coating Properties, Thin Film Applications, Value of Coatings

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Overview & Key Takeaways

This guide provides engineers with a practical, side-by-side comparison of Parylene coatings vs. traditional liquid conformal coatings to support informed material selection for high-reliability electronics. While both technologies offer protection against moisture, corrosion, and electrical failure, their performance, application methods, and long-term reliability differ significantly.

Parylene provides highly uniform coverage: Its vapor deposition process creates a thin, pinhole-free coating that evenly protects complex geometries, including edges, gaps, and under components.
Liquid coatings are more variable in application: Spray, dip, or brush methods can lead to uneven thickness, including pooling, edge thinning, and shadowing around dense components.
Parylene offers superior barrier protection: It delivers strong resistance to moisture, chemicals, and environmental exposure, making it well-suited for harsh and high-reliability applications.
Electrical performance is more consistent with Parylene: High dielectric strength and low dielectric constant support compact designs and reliable insulation performance.
Thinner coatings can achieve high performance: Parylene typically meets protection requirements at much lower thicknesses compared to liquid coatings.
Liquid coatings can be more cost-effective for simpler use cases: They are often easier to apply at scale and may be sufficient for less demanding environments.
Both technologies can meet industry standards: However, Parylene generally provides greater consistency and reliability across a wider range of operating conditions.
Material selection should be application-driven: Parylene is ideal for mission-critical, miniaturized, or harsh environments, while liquid coatings are often chosen for cost-sensitive or lower-risk applications.

Key performance differences between Parylene and liquid films

Engineers evaluating environmental protection for their electronics often hear two broad options: traditional liquid conformal coatings (acrylic, urethane, silicone, epoxy) and vapor-deposited Parylene. On paper, both categories promise corrosion resistance, dielectric insulation, and improved reliability – but their performance envelopes and trade-offs differ.

Material Properties

A structured comparison starts with material properties. Parylene films, deposited via chemical vapor deposition (CVD), form ultra-uniform, pinhole-free layers that completely encapsulate complex three-dimensional geometries. Because they are deposited in a vacuum directly from the gas phase, they exhibit extremely low water vapor transmission, high dielectric strength, and excellent chemical inertness at thicknesses often half of what a liquid conformal coating would require to meet the same standard. Liquid conformal coatings, by contrast, are applied from solution. Issues like edge-thinning, pooling, and coverage shadows must be actively managed, especially around sharp leads, tall components, and under low-standoff packages. These coatings can still perform well in many environments, but they generally need to be thicker to compensate for coverage variation. Their permeability and long-term stability in the presence of aggressive fluids are typically inferior to Parylene.

Download Datasheet

Electrical Performance

Electrical performance is another key differentiator. Parylene’s combination of high dielectric strength and low dielectric constant supports tight creepage and clearance distances, high-speed signaling, and compact high-voltage designs. Liquid coatings vary widely by chemistry, and some, such as silicones, can deliver good electrical insulation, but they do not match Parylene’s combination of thinness and robustness. When comparing performance, it is important to anchor the discussion in recognized standards and test methods. Documents such as IPC-CC-830 and IPC-HDBK-830 define qualification tests – dielectric withstand, insulation resistance, thermal shock, and more – that any coating technology must pass. External resources, such as this technical overview of IPC-CC-830, provide helpful background for teams new to these standards. In practice, both Parylene and liquid coatings can be engineered to pass such tests. The distinction emerges over the product lifecycle: how coatings behave after years of thermal cycling, exposure to mixed contaminants, and mechanical stress. Here, the consistency and barrier strength of Parylene give it a clear edge for mission-critical applications, while liquids may be entirely adequate for less demanding environments.

Process, throughput, and cost tradeoffs engineers must weigh

Once engineers understand the performance deltas, the next question is practical: how do process, throughput, and cost compare – and where do they tip the decision one way or the other? Liquid coatings are typically applied by spray, dip, or selective coating equipment. They can be integrated directly into SMT or box-build lines, and with the right fixturing and robotics, they support high throughput. Drying and curing steps add time and WIP, but continuous ovens and UV curing can compress that overhead. Material cost per unit area is relatively low, although multi-pass spray processes can increase consumption.

Parylene, by contrast, is a batch vacuum process. Assemblies are loaded into a chamber, masked areas protected, and a defined amount of dimer is vaporized and polymerized until the target thickness is reached. There is no liquid phase, so there is no drying or curing, and no VOCs to manage. Cycle times are measured in hours, and throughput is managed by optimizing chamber loading and recipe time. For low to medium volumes, especially in medical or industrial markets, this batch nature is often acceptable. In high-volume segments such as consumer electronics and automotive, the key is industrialization: well-designed racks that maximize chamber density, robust masking strategies, and process controls that minimize variation. Resources like HZO’s conformal coating guide and its thin-film webinar series can help internal teams understand these dynamics.

VIEW A RELEVANT WEBINAR

Cost

Cost needs to be considered at a lifecycle level, not just per-unit process cost. Liquid coatings look inexpensive from a BOM and line-time standpoint, but field failures, returns, and latent corrosion can easily erase that advantage. Parylene’s per-unit processing cost is higher, but its barrier performance, electrical insulation, and long-term stability often translate into fewer failures and warranty claims. From a supply-chain perspective, Parylene also opens up design options that can reduce system-level cost. For example, replacing bulky mechanical seals with a thin-film barrier can enable smaller housings, lower material usage, or simplified assembly steps. In some applications, it may allow the use of lower-cost substrate materials because the coating provides the needed environmental robustness. The key for decision-makers is to model both direct and indirect costs. Look beyond cycle time and dimer price to include the cost of field returns, rework, safety margins in design, and even reputational impact. Many organizations find that for a subset of mission-critical assemblies, Parylene is the more economical choice once the full picture is visible.

When to specify Parylene and when liquids are sufficient

Ultimately, the decision to use Parylene or a liquid conformal coating should be made at the design stage, informed by reliability targets, regulatory requirements, and business constraints. As a starting heuristic, Parylene tends to be the right fit when:

The assembly operates in a harsh or mixed environment (liquids, salts, industrial gases, biological fluids)
Failure carries high safety, regulatory, or brand risk
Dense circuitry and fine pitch increase the risk of leakage and arcing
There is value in shrinking the form factor or simplifying mechanical sealing
Qualification to demanding standards such as IPC-CC-830, UL 746E, or medical biocompatibility is required

Liquid coatings remain a strong choice when:

The environment is moderate and mostly limited to humidity or occasional condensation
Assemblies are easily accessible for rework and replacement
Time-to-market and line simplicity outweigh maximum robustness
Coating is used primarily as a cleanliness and dust barrier rather than a primary corrosion or chemical barrier

In many organizations, the most effective strategy is a hybrid one: reserve Parylene for the 10–30% of products where its capabilities align with high criticality and severe environments, and use optimized liquid coatings elsewhere. This portfolio view aligns coating spend with risk while leveraging existing infrastructure. Engineers and program managers can strengthen their case for the right coating choice by referencing external technical resources.

Overviews of conformal coating standards, such as IPC-CC-830, and design handbooks, like IPC-HDBK-830, can provide a neutral framework for internal discussions. By combining those references with HZO’s own data on Parylene performance – for example, its work on high-dielectric-strength, low-permeability films and scalable deposition chambers – engineering teams can build a clear, evidence-based story: where Parylene is essential, where liquids are sufficient, and how to implement both efficiently. With this clarity, coating stops being a late-stage checkbox and becomes an integral part of how reliable, high-performing products are engineered from day one.

HZO Celebrates Pi Day 2025

March 13, 2025 / by Mallory McGuinness-Hickey posted in Parylene, Protection Capabilities, Value of Coatings, About HZO

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In honor of Pi Day 2025, the HZO Team in Morrisville, North Carolina, headquarters honored our beloved Raspberry Pi computer that has been running and displaying our demo video - while submerged continuously underwater for almost 1,000 days.

The Raspberry Pi PCBA is coated with Parylene coating using a vapor deposition process. Parylene coating enhances and protects electronic components, allowing them to operate reliably through harsh electrical activity, exposure to harmful chemicals, and more.

The team took pictures with the Raspberry Pi, which has become like a family member, and wrote notes of encouragement for it as it reaches day 1,000. Happy Pi day!

Check out the slideshow below.

An Overview of Our Parylene Coating Equipment

September 26, 2024 / by Ryan Moore posted in Parylene, Coating Process

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The development of our coating technology began in 2007. We've come a long way since, filing more than 200 patents and protecting millions of digital devices.

Today, we want to nod to our origin story. We also want to introduce, at a high level, a key material that is a building block of our technology.

Learn more about the Parylene process and Parylene properties.

Parylene Protection

Parylene (or Poly(p-xylylene) as it’s also known) is a protective coating. It's deposited using a chemical vapor deposition process. The material is a moisture-resistant, dielectric thin film barrier. It has been used for over five decades on many corrosion-resistant products. Parylene is biocompatible, has superior barrier properties at 50% thickness and is chemical-resistant. Think big. Think powerful. Parylene has been protecting equipment and products in some of the world's most advanced industries for decades.

Read more about WHY ENGINEERS USE PARYLENE

HZO has developed its proprietary technology using Parylene as a building block. Over the years, it has improved its chemistry and processes. It also automated its Parylene masking and removal equipment. These innovations form a unique and powerful conformal protective solution.

Parylene Overview

So why have most people never heard of it? A major obstacle to wider adoption of Parylene is its high cost. This affects many products, including consumer devices.

Learn more about Parylene coating cost considerations

The Parylene deposition system and its raw material are expensive. There have been challenges with scalability, manufacturing, and device complexity. There has also been a manual process for masking and demasking sensitive areas that need protection from protective layering.

To the credit of Parylene companies that have been in that market for much of this journey, the technology has improved dramatically over time. The material has a sterling reputation in certain markets where development has been focused. But what about other industries that need the same kind of powerful protection?

HZO Parylene Coating Equipment Broadens the Scope

HZO has expanded the use of this powerful, organic material. It has made it available to companies and manufacturers that had not considered it an option until now. The application’s utility is what separates HZO from other companies in the Parylene space.

We talk a lot about the power of the Total HZO Solution. This includes more than our thin-film protective layering technology. That technology protects digital devices from corrosive liquids. It also includes advances in equipment, integration, and specialized processes. These are required to protect some of the world's most complex digital devices. HZO is a leader in custom solutions for digital devices. Years of work on the technology have made it so. Parylene is part of that solution.

Our ongoing innovations benefit every company we work with. HZO has made Parylene's benefits more accessible and affordable than ever. As a result, more sweat and corrosion-resistant products are reaching consumers. The change in performance is starting to get noticed, and the cry for better protection on consumer devices has never been stronger.

Parylene C Biocompatibility: Properties, Safety, and Medical Use Cases

September 24, 2024 / by Mallory McGuinness-Hickey posted in Parylene, Coating Properties

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Overview & Key Takeaways

Parylene C is biocompatible and meets USP Class VI and ISO 10993 standards — the two primary benchmarks for medical device materials. It is the most widely deployed variant in the Parylene family for medical and implantable device applications. Its chlorinated para-xylylene structure delivers superior moisture barrier performance and chemical resistance while maintaining full biocompatibility with human tissue and fluids. Engineers evaluating Parylene C should weigh its exceptional protective properties against its mechanical limitations relative to bulk structural materials.

USP Class VI and ISO 10993 compliance: Parylene C meets the two primary biocompatibility standards for medical devices, including passing cytotoxicity, sensitization, genotoxicity, and implantation tests. Independent third-party testing confirms it causes no measurable harm to tissues or body fluids.
Chemical inertness: Parylene C does not leach plasticizers, solvents, or catalysts into surrounding tissue. Deposited as a pure polymer with no additives, it resists bodily fluids, enzymes, and varying pH levels without degradation over time.
PFAS-free formulation: Unlike Teflon (PTFE), Parylene C contains no per- or polyfluoroalkyl substances and is both REACH and RoHS compliant — a meaningful differentiator for manufacturers navigating tightening PFAS regulations.
Pinhole-free conformal barrier: Chemical vapor deposition produces a continuous, void-free coating at thicknesses as low as 1 micron, conforming to complex geometries and fine features while fully isolating device surfaces from biological environments.
High dielectric strength: Parylene C achieves up to 7,000 V/mil, providing reliable electrical insulation for implantable electronics, sensors, and active devices operating in the body.
Tradeoff vs. structural materials: Parylene C is not suitable as a load-bearing or structural material — its tensile and yield strength are lower than metals and ceramics. Applications requiring mechanical strength must pair Parylene with a rigid substrate. CVD application also requires specialized equipment and process integration not needed for simpler liquid coating methods.

Parylene C is widely considered one of the most biocompatible conformal coatings used in medical devices. It forms a chemically inert, pinhole-free barrier that protects both the device and the human body from harmful interactions.

Because of its stability, low permeability, and proven safety profile, Parylene C is commonly used in implants, surgical tools, and wearable medical electronics.

What Does "Biocompatibility" Mean for Parylene C?

Biocompatibility refers to a material's ability to perform safely in contact with the human body without causing adverse reactions such as toxicity, inflammation, or immune response.

Parylene C achieves this by acting as a non-reactive, protective barrier between device materials and biological environments. It prevents leaching, corrosion, and chemical interaction — key risks in medical applications.

What Biocompatibility Standards Does Parylene C Meet?

Parylene C satisfies both primary biocompatibility standards used by medical device manufacturers and regulatory bodies:

USP Class VI — the highest classification in the U.S. Pharmacopeia's plastics testing protocol, requiring passing results for systemic injection, intracutaneous injection, and implantation tests
ISO 10993 — the international standard series for biological evaluation of medical devices, covering cytotoxicity, sensitization, and genotoxicity, among others

Independent testing confirms Parylene C passes both standards. Its chemical inertness — meaning it does not react with bodily fluids, enzymes, or varying pH environments — is the primary reason for its compliance.

Why Is Parylene C Considered Biocompatible?

Chemically inert: Does not react with bodily fluids or tissues
Pinhole-free coating: Provides complete, uniform coverage with no gaps or voids
Low permeability: Blocks moisture, gases, and contaminants
Non-toxic barrier: Prevents harmful substances from leaching into the body
PFAS-free: Contains no per- or polyfluoroalkyl substances — REACH and RoHS compliant

Parylene C's ability to create a continuous, defect-free film is critical. Unlike liquid coatings, it forms a uniform layer even on complex geometries, reducing exposure risks.

Download datasheet

Key Properties That Enable Biocompatibility

1. Exceptional Barrier Protection

Parylene C has extremely low permeability to moisture and gases, which helps prevent corrosion and contamination in harsh biological environments.

2. Chemical Resistance

It resists a wide range of chemicals, ensuring long-term stability when exposed to bodily fluids, enzymes, and varying pH levels.

3. Electrical Insulation

Parylene C has a dielectric strength of up to 7,000 V/mil, making it ideal for implantable electronics and sensors that must function reliably in the body.

4. Conformal Coverage

The chemical vapor deposition (CVD) process allows Parylene to coat intricate surfaces evenly at thicknesses as low as 1 micron, eliminating gaps that could compromise safety or device performance.

How Does Parylene C Compare to Other Medical Coating Materials?

Property	Parylene C	Silicone	Epoxy	Teflon (PTFE)
Biocompatibility Standard	USP Class VI, ISO 10993	ISO 10993	Moderate	ISO 10993
Moisture Barrier	Excellent	Moderate	Good	Good
Conformality	Complete coverage	Limited	Limited	No
Thickness Control	Precise (micron-level)	Variable	Variable	12–25 µm
PFAS-Free	Yes	Yes	Yes	No
Dielectric Strength	Up to 7,000 V/mil	~500 V/mil	~400 V/mil	~2,000 V/mil

This combination of properties is why Parylene C is often selected for critical medical and implantable applications — particularly where Teflon alternatives are needed due to tightening PFAS regulations.

Common Medical Applications of Parylene C

Implantable devices (pacemakers, stents, cochlear implants)
Cardiac assist devices — reduces thrombogenicity without altering device geometry
Needles and cannulas — reduces friction for easier insertion and improved patient comfort
Wearable medical electronics
Surgical tools and instruments
Microelectromechanical systems (MEMS)
Drug delivery devices

The global Parylene market was valued at $98.38 million in 2023 and is projected to grow to $118.52 million by 2030, driven in large part by expanded medical device applications.

Does Parylene C Improve Device Safety?

Yes. Parylene C enhances safety in two critical ways:

Protects the body: Prevents exposure to device materials and potential toxins by creating a chemically inert barrier between the substrate and surrounding tissue
Protects the device: Shields electronics from moisture, corrosion, and biological degradation — extending functional lifespan in demanding in-vivo environments

What Are the Limitations of Parylene C in Medical Applications?

While Parylene C is highly biocompatible, it is not universally ideal for every application:

Mechanical load-bearing: Parylene's tensile strength is lower than metals and ceramics — it is not appropriate for structural applications without a rigid substrate
Adhesion on certain substrates: Some materials require surface preparation or adhesion promoters before coating
Application process complexity: CVD requires specialized equipment and batch processing, unlike simpler dip or spray coating methods

These challenges are typically addressed through proper engineering and process optimization — and in most cases, Parylene's performance advantages justify the added process complexity.

FAQ: Parylene C Biocompatibility

Is Parylene C safe for implantable medical devices?

Yes. Parylene C meets USP Class VI and ISO 10993 biocompatibility standards — the primary requirements for implantable and body-contact medical devices. It is non-toxic, physiologically non-reactive, and has a decades-long track record in implantable applications, including pacemakers, stents, and cochlear implants.

Is Parylene FDA approved?

Parylene itself is not an FDA-approved material — the FDA approves devices, not coating materials in isolation. However, Parylene C is widely used in devices that have received FDA clearance or approval, and its USP Class VI and ISO 10993 compliance makes it well-suited for inclusion in FDA submissions.

Does Parylene C prevent corrosion?

Yes. Its low permeability, pinhole-free structure, and chemical inertness make Parylene C highly effective at preventing corrosion caused by moisture, bodily fluids, and enzymatic activity.

Is Parylene PFAS-free?

Yes. Parylene C contains no per- or polyfluoroalkyl substances (PFAS) and is both REACH and RoHS compliant — unlike Teflon (PTFE), which is classified as a PFAS material. This makes Parylene a strong alternative for manufacturers navigating tightening PFAS regulations.

How does Parylene compare to silicone coatings?

Parylene offers better moisture resistance, more precise thickness control, and more uniform coverage — especially on complex geometries. Silicone coatings are applied at significantly greater thickness and cannot achieve the pinhole-free conformality Parylene delivers via CVD.

How is Parylene applied to medical devices?

Parylene is deposited via chemical vapor deposition (CVD) — a room-temperature process that conformally coats all exposed surfaces regardless of geometry. The process leaves no liquid residue and requires no curing step.

Read about how to incorporate Parylene into your process

Learn More About Parylene Coatings

If you're evaluating Parylene for medical or high-reliability applications, understanding its advantages and limitations is critical.

Explore more about Parylene coating properties or learn how it compares to other materials in our Parylene vs. liquid coatings guide.

Learn more in our webinar, Parylene: Pros, Cons, and Practicalities

Parylene Coating Removal - Methods & Best Practices for Each

September 12, 2024 / by Mallory McGuinness-Hickey posted in Parylene, Coating Process

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Parylene coatings present unique challenges when it comes to rework and removal. They often outperform other conformal coatings. Parylene has better barrier properties, uniform coverage, and performance in thinner layers.

Learn more about what Parylene is used for.

Additionally, Parylene's chemical resistance can withstand corrosive gases and liquids. It also performs in extreme temperatures and high electrical activity.

Want to know if HZO Parylene meets your specifications?

Download Datasheet

But, the properties that make Parylene the "gold standard" of conformal coating can also make it hard to remove. Thankfully, you can use methods to remove and rework Parylene when needed.

When Do You Need to Remove Parylene?

From time to time, it is necessary to rework or remove coating. Sometimes, job specifications change or a Parylene vendor incorrectly applies the coating.

What is Parylene Delamination?

One example of poor application is Parylene delamination. This is when the conformal coating separates from the coated surface. This results in an unattached, torn, non-conformal coating and an unacceptable finish. Delamination defeats the purpose of Parylene coatings. It must be avoided at all costs. Even partial lifting can render the protective coating useless.

What Causes Parylene Delamination?

Many causes of Parylene delamination exist. One is demasking, a standard process. It creates a need for high-quality inspections after production. Other causes include:

Coating porosity: A vapor pressure difference creates a risk of moisture intrusion into the substrate. Pressure fluctuations and temperature changes create osmotic pressures. These separate the coating from the component.

Incompatible materials: The Parylene coating must bond with the component surface for successful coverage. When the Parylene and the surface are incompatible, they create incongruous surface energies. This causes minimal bonding.

Contaminated surfaces: Improperly cleaned component surfaces do not support adhesion.

Regardless of the reason, the resulting Parylene removal must be efficient and safe. It must protect the coated substrate's integrity.

The following methods are popular ways to approach Parylene removal.

How Do You Do Mechanical Parylene Removal?

Parylene's strength and uniformity make it tough to remove. So, be careful with mechanical methods. They may damage the final product. However, Parylene is a soft polymer. So, mechanical methods may remove it.

Methods like picking, cutting, and scraping are effective. But, they may damage components, substrates, and delicate track lines. This type of removal requires considerable attention and care. Good spot removal is possible with proper masking. But, mechanical methods may be unreliable for larger surfaces.

How to Remove Parylene with Micro-Abrasion

Micro-abrasion is a process performed with automated or handheld systems. It targets a specific area by blasting the Parylene coating with inert gas or dry air and abrasive media. This removal method is suitable for both whole board and spot removal. It is generally easy to put in place, quick, cost-effective, and environmentally friendly.

Can You Use Thermal Removal With Parylene?

Parylene can withstand high temperatures. But, a high-temperature oven or soldering iron can remove it in small, specific areas. As heat is applied, the coated component rises from the board and lifts off.

This technique may be adequate for small repairs. It is less reliable for large surfaces. But, it can still be effective for some jobs. However, residues and discoloration may occur. Parylene's high melting point may damage heat-sensitive substrates. Thermal removal can be hard to manage. It's not recommended without Parylene experts' help.

thermal removal parylene removal method

Which Chemical Can Remove Parylene?

Parylene is chemically inert, resisting chemical degradation. But, one chemical has been used to strip Parylene from substrates and components. It is a colorless organic compound, tetrahydrofuran (THF), with the formula (CH2)4O. This solvent softens the Parylene coating. It temporarily loosens the bond between the substrate and the coating. At this point, the Parylene can be lifted off with tweezers. THF can remove Parylene, but it may damage the coated part. Use the solvent only for complete coating removal. For the security of the components under the coating, consider other removal methods before using TFH.

Laser Ablation for Parylene Removal

Laser ablation is a process that removes material from a surface by irradiating it with a laser beam. The beam can cut, drill, or mark delicate materials, providing precise removal. At HZO, a laser ablation process converts Parylene to gas or plasma with pulsed laser sources. This method is cost-effective for complex removals. It gives better results. It can also service 3D devices and Parylene-free areas.

Conclusion

There are many effective methods to remove Parylene should the need arise. Each method has its strengths. So, you must know your options. Then, choose the best method for your project.

If you need Parylene removal or want to discuss your project with experts, please message us today. Removing Parylene can be tough. But, a skilled company can simplify and lower the cost of the job. We can help with scalable Parylene equipment and Parylene masking automation. We can also address concerns about the cost of Parylene services.

ADAS Design and Validation for the Real World - Automotive Coatings

June 15, 2023 / by Mallory McGuinness-Hickey posted in Parylene, Coating Properties, Thin Film Applications

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Advanced driver assistance systems (ADAS) continue to expand in features and functionalities. Standard offerings may include adaptive cruise control, park assist, blind-spot detection, lane departure, RADAR, emergency braking, tire pressure monitoring, and LiDAR systems.

When consumers purchase a vehicle with ADAS safety features, they believe they have a layer of protection to be entirely relied on. In reality, though, without a methodical, effective ADAS component design that accounts for real-life situations, these features are no more than crutches.

In addition to the ethical argument that safety should be an underlying principle of ADAS design, liability concerns create a business case for ADAS components that dependably function in the typical automotive service environment.

As ADAS designers evaluate the risk of harm, they may ask about the probability of exposure to an element or situation that could cause failure. They may ascertain how severe the resulting damage may be and determine how controllable the issue is if it should occur.

The risk of harm is high in instances such as premature ADAS component failure due to harsh environments. ADAS PCBAs and components will inevitably encounter corrosive elements, humidity, thermal shock, water ingress, and other environmental factors that compromise electronics. If this ADAS component should fail as a result, consumers relying on a safety feature could incur severe damage and liability, and in terms of controllability, there is not much that can be done upon critical component failure.

ADAS component reliability through harsh environments is a high-risk issue. Therefore, design engineers must prioritize safeguarding ADAS components from failing in these circumstances and verifying their safety in real-life situations. Testing and validation can become problematic when legacy methods such as gaskets and seals bolster ADAS reliability.

Possible Issues with ADAS Testing Protocols and Traditional Reliability Methods

Issues with ADAS reliability testing protocols may include:

● Testing must confirm that a system will handle situations that can be predicted and that ADAS will reliably work under unknown circumstances.
● Proper validation and verification can entail testing many conditions, particularly as vehicle design shifts towards fully autonomous vehicles.
● Testing for scenarios on a test track may be impractical when methods such as seals and gaskets are used for ADAS reliability.

For example, to test that a seal will continue to prevent ingress while exposed to vibration, you might have to wait for weather conditions to occur naturally, including snow, rain, or humidity. Although you can use equipment to mimic these weather conditions, this will add to testing complexity.

It's Possible to Simplify ADAS Reliability

As noted, seals and gaskets can become dislodged in many situations, which would have to be recreated and accounted for to validate and verify ADAS component reliability if they are the primary protection method. This unpredictability raises complications during the design and validation process.

Furthermore, as more features are built into vehicles, more components will need to fit in. The bulk of seals, potting, and traditional conformal coatings can lead to more design challenges. These conventional methods can also complicate lightweighting efforts as they add unnecessary weight.

HZO’s proven, trusted Parylene coatings solve these testing and design challenges. These conformal coatings come in several types, including Parylene N, Parylene F (VT-4), and Parylene C, demonstrating excellent performance in mission-critical applications for decades, in part due to uniform coverage, barrier properties, and less stress on mechanical structures.

HZO Coatings for Automotive Corrosion Protection

We’ve proven that our coatings can deliver as much – or more – flexibility, fungus resistance, flammability, dielectric withstanding voltage, thermal shock, moisture, and insulation resistance at a fraction of the mass of conventional coatings, passing the IPC CC-830C test at 50% of the film thinness. Unlike seals and gaskets, Parylene does not stop providing protection when exposed to unpredictable situations, such as drops and falls. The coating is well studied and, when appropriately applied by engineers who understand the parameters of an application, will withstand the lifecycle of the product it is enabling.

Class	Type	Specimen – Average Coating Thickness [μm]
		1	2	3	4
XY	Parylene N	25	25	23	23
XY	Parylene C	31	30	30	32
XY	Parylene F	46	36	43	29
AR/UR	Acrylic	73	73	69	72
SR	Silicone	102	99	114	154
AR/UR	Acrylated Polyurethane	91	91	107	107

Below, you can see how our coatings performed in automotive validation tests.

Contents	Requirements	Test Results
Operations Test	Operate for 24 hours at 23 Degrees C	Operate for 24 hours at 23 Degrees C
Coating Property	No Pinhole and Uncoated Area	No pin hole and uncoated area Coating thickness 225±3 [μm]
Electrical Test	Dielectric withstanding voltage: Over 1.5 [kV] Insulation resistance: Over 10 [GΩ] IPC-B-25A standard test board pattern Dv	Over 1.5 [Kv] Over 10 [GΩ]
Corrosion Test	Salt spray (35 °C, NACI, 96 hours): No corrosion on chip leads	No corrosion on chip leads

Enhanced Component Reliability and Increased Resistance to Fluids and Oils

The automotive operating environment includes exposure to chemicals such as oil, antifreeze, standing water, and cleaning fluids. HZO Parylene coatings offer dependable protection for various leak, environmental, splash, and submersion test requirements.

Protection Characteristics	Unprotected PCB	Mechanical Seal	Silicone/Acrylic Coatings	Parylene Coating
Protection Barrier	None	Good, but can be compromised with drops & temperature.	Good, but can be thick & porous depending on the application.	Excellent. Can peel if not properly applied.
Hydrophobic	No	No	Yes	Partial
Thickness	N.A.	Millimeters	μm – Millimeters	2μm – 50μm
Protection Against Water	Poor	Good – Ingress Poor – Penetration	Good	Excellent
Salt/Chemical Protection	Poor	Poor	Varies	Excellent
Durability	Low	Varies	Varies	High
Submersion Test Time to Failure	Seconds (IP Rating N.A.)	Varies	Varies	Days to Weeks (IPX7 – IPX8)

When used as a redundant solution along with legacy methods, our coatings can provide more robust, reliable protection and the ability to reduce sealing, thereby minimizing spacing and weight issues. As the visual below indicates, a mechanical seal can easily be breached. With HZO’s Parylene protection, moisture ingress is not an issue.

Contact HZO for Automotive Component Coatings

If you are interested in Parylene and would like to speak to our industry-leading applications engineering team, please reach out with a message or fill out a quote form to understand your application needs and provide a tailored solution.

Parylene Conformal Coatings - Parylene Conformality Explained

June 6, 2023 / by Mallory McGuinness-Hickey posted in Parylene, Coating Properties

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Parylene (p-polyxylylene) conformal coatings are unique due to their capacity to be polymerized and deposited by the chemical vapor deposition (CVD) method onto surfaces near room temperature. As a result of this process, pinhole-free, high-purity, extremely thin coatings are formed out of dimer materials.

Regarding conforming to complex or unusual surfaces, Parylene is one of the best polymer coatings for moisture resistance. This attribute and the fact that Parylene is a stable chemical compound that creates an excellent barrier make it the optimal choice where resilient electronic products are a mandate. But why is Parylene coating conformal?

Download HZO’s Parylene datasheet to learn more about Parylene’s properties

Download Datasheet

Why is Parylene Coating Conformal?

Liquid coatings with application methods such as dipping, brushing, or spraying may cause the coatings to exhibit meniscus forces or pull away from edges, which does not occur with Paylene deposition. With CVD, the coating penetrates around and beneath closely spaced components with consistent, uniform buildup, allowing for substantial physical and electrical protection with a substantially thinner layer than conventional coatings.

Parylene Deposition Process

Thus, the Parylene coating process explains why Parylene is so conformal. You can read an in-depth description of the CVD process versus PECVD in our blog on the subject; below are some general benefits of CVD:

Download a visual explanation of the process

Download Infographic

CVD produces coatings with complete coverage even around and beneath closely spaced chips and wires.
CVD deposits Parylene molecule by molecule onto substrates with precision and control.
The Parylene deposition process requires no catalyst, hardener, or heat curing.
Polymerization does not release harmful by-products, as with other conformal coatings.

Chemical vapor deposition process

When Parylene polymers are deposited from the vapor phase with the CVD process, all sides of a component are impinged by the gaseous monomer and uniformly coated. This feature of the process is responsible for why Parylene coating is conformal.

Importance of Conformality and Uniformity

Truly conformal coverage occurs when a film precisely follows the coated component’s geometry. Conformality allows for the optimization of surface properties regardless of the shape of the part and ensures that microdevice properties such as conductance do not vary due to significant variations in thickness. Uniform thickness is critical to prevent proper reinforcement against degradation and wear.

Parylene Conformality Compared to Liquid Coatings

Along with performance concerns, achieving uniformity improves production factors such as yield rates and repeatability. With the chemical vapor deposition process, engineers have confidence that there will not be thickness fluctuations from product to product and that specs are being met. By ensuring optimum coating deposition performance is met, you can lower your total cost of ownership by keeping your repeatability and yield on target.

Parylene Conformal Coating Service with HZO

However, although a process may achieve repeatable, uniform thickness distributions, this does not mean it is viable for your company – uptime and upfront costs must also be considered. Parylene has traditionally only been used for mission-critical applications such as medical products. HZO, a turnkey CVD process provider, has made Parylene and its application feasible for most industries for years. Our engineers have crafted capital coating equipment that addresses upfront cost concerns and makes Parylene scalable. If you are interested in the powerful barrier properties of Parylene films and the benefits of its vacuum deposition process, reach out today to speak to one of our engineers.

Parylene Masking - General Concepts Explained

January 28, 2022 / by Mallory McGuinness-Hickey posted in Parylene, Coating Process

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Conformal coatings are an excellent way to increase the reliability of electronic components in harsh environments. However, this protection can be too much of a good thing without processes to ensure certain areas remain coating-free.

These polymeric films can inhibit the critical functions of specific functions, but the masking process resolves this issue. With proper masking, you can benefit from conformal coating protection without losing functionality.

What is Masking?

Masking is applying a temporary film, boot, tape, or plug to designated assembly components to prevent them from being coated. While masking is important for conventional coatings such as acrylics, epoxies, urethanes, and silicones, Parylene has unique qualities that create a critical need to ensure it is done right.

Quick Introduction to Parylene Masking Techniques

For general guidance on conformal coating masking, the IPC-HDBK-830A handbook provides a good reference. However, because the coating process causes Parylene molecules to penetrate any surface area accessible to air, operators must ensure that all coating keep-out areas resist Parylene coating application, which requires domain expertise.

HZO uses proprietary masking equipment, and our engineers build and customize techniques for every project. However, a short description of general methods follows below.

Parylene masking techniques typically involve precisely sizing materials such as tapes, form-in-place gaskets, and boots to designated masked regions. After applying materials to the appropriate areas, a masking operator will allow peelable masking materials to dry before starting the CVD process, coating the entire component. After coating, the masking material is carefully removed.

Why Proper Masking for Parylene Coating is So Critical

Parylene’s exceptionally high dielectric strength requires you to mask the right areas diligently. A PCBA coated with Parylene would benefit from electrical insulation protection. However, if the connectors on that same PCBA get covered, you won’t be able to plug it in or make connections.

Another reason you must get your Parylene masking process correct is the film's incredible conformality. Where Parylene is allowed to penetrate, pins and moving parts will be completely encapsulated. Although this cohesive and thorough presence of coating is typically considered a benefit, additional cost and labor to remove the Parylene from the keep-out areas will be required with incorrect masking implementation. In other words, it’s best to prevent instead of rework, which can be challenging due to Parylene’s strong chemical resistance properties.

Why It Can Also Be More Complicated

When you mask for Parylene application, the stakes are higher. Once it’s on, removing the coating will be a struggle without a knowledgeable partner with tools and techniques to make rework easier. The fact that masking for Parylene is also more complex, requiring more skill, raises further complications.

Without skill and experience, masking for Parylene is more challenging than general conformal coating masking due to the chemical vapor deposition process (CVD) used to apply the coating.

Learn about Parylene Thickness

Unlike conventional conformal coatings applied as liquids, Parylene is applied as a vapor, which means you are masking against a gas. Therefore, a much better barrier is required with the Parylene masking process, as vapor can more easily bypass masking materials.

Other masking considerations include:

The need to validate if all components are hermetically sealed or not due to the vacuum nature of the CVD process
Chamber maintenance
Masking more than just keep-out locations may be required
The need for specific fixturing
Materials need to be thoroughly cured before coating, and outgassing should be avoided

The list below includes components that, in many cases, should not be coated:

MEMs
Actuators
Mating connectors and pins
Test points needed before assembly
Ground contacts

Parylene Coating With HZO

If you are masking for Parylene, you must implement the process correctly. Further, Parylene masking requires considerable expertise and experience to identify factors affecting masking success. These might include Parylene masking materials, the Parylene type, and the different areas that must be coated. Proper timing is also essential, as there is a relationship between the masking and coating processes. Any timing issues can impede coating quality. Managing electrostatic discharge is also a concern when masking.

Fortunately, our engineers have years of this experience, creating custom masking plans for customers with electronic products of all sizes, shapes, and functions. We have also developed industry-leading masking equipment that can automate and semi-automate the process for larger productions.

Reach out today if you would like a consultation to discuss why to use Parylene, our scalable Parylene coating equipment, or our automated masking processes that decrease Parylene coating costs.

What is Parylene Coating? Uses, Properties, and How to Choose It

October 21, 2021 / by Mallory McGuinness-Hickey posted in Parylene, Thin Film Applications, Value of Coatings

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Overview & Key Takeaways

Parylene coating is a high-performance conformal coating used to protect electronics and other sensitive components from moisture, chemicals, corrosion, and environmental stress. Applied through a chemical vapor deposition (CVD) process, Parylene forms an ultra-thin, uniform, pinhole-free barrier that conforms to complex geometries, edges, gaps, and delicate surfaces.

Engineers use Parylene coating when products need reliable protection without adding bulk or weight. This guide explains what Parylene is, what it is used for, its key properties, how the coating process works, and how to determine whether it is the right choice for your project.

Parylene coating is an ultra-thin, high-performance protective barrier: It provides uniform, pinhole-free coverage across complex geometries and sensitive components.
Parylene is used in demanding applications: Common uses include medical devices, aerospace systems, automotive electronics, industrial equipment, and consumer electronics.
Parylene properties make it stand out: It offers strong moisture resistance, chemical resistance, dielectric strength, and conformality.
The Parylene coating process enables uniform protection: Chemical vapor deposition creates a consistent film at the molecular level, even on tight gaps and intricate surfaces.
Parylene is especially effective in harsh environments: It helps protect electronics exposed to humidity, chemicals, corrosion, temperature changes, and contaminants.
Different Parylene types serve different needs: Parylene N, C, and D each provide different balances of dielectric, barrier, and thermal performance.
Parylene is not always the default choice: It is best when performance, reliability, and protection are more important than the lowest upfront cost.
Selection should be application-driven: Engineers should evaluate operating environment, electrical requirements, geometry, lifecycle expectations, and total cost of failure.

What is Parylene Coating?

Parylene is a polymer coating deposited as a vapor rather than applied as a liquid. This makes it different from traditional conformal coatings such as acrylic, silicone, urethane, or epoxy. Instead of relying on spray, dip, or brush application, Parylene is formed in a vacuum deposition process that allows it to coat exposed surfaces evenly and consistently.

Parylene has excellent dielectric strength and unmatched barrier properties. The coatings resist corrosive gases, moisture, and solvents, ensuring product longevity.

Because of this process, Parylene coating is known for being:

Ultra-thin
Highly uniform
Pinhole-free
Conformal to complex geometries
Lightweight without sacrificing protection

What Is Parylene Used For?

Parylene is used to protect components and assemblies that need dependable performance in environments where moisture, chemicals, corrosion, or electrical stress could cause failure. It is especially valuable when products have complex geometries, dense electronics, or strict reliability requirements.

Medical Device Applications

Parylene is widely used in medical devices because it provides thin, uniform protection without significantly changing device dimensions. It is often selected for implantable devices, wearable technologies, diagnostic equipment, and other sensitive components that benefit from reliable barrier protection.

Download our medical brochure

Automotive and Aerospace Applications

Automotive and aerospace electronics often operate in demanding environments that expose components to temperature extremes, humidity, chemicals, vibration, and contaminants. Parylene helps protect sensors, electronic control units (ECUs), connectors, and other assemblies that must perform reliably over long service lives.

Watch a video about why automotive OEMs use Parylene:

Consumer Electronics Applications

Parylene is also used in consumer electronics where manufacturers need lightweight, thin-film protection against moisture, sweat, spills, and daily environmental exposure. Its ultra-thin nature makes it well-suited for compact and miniaturized devices.

Read a hearables use case

Industrial and IoT Applications

Industrial electronics and IoT devices often face corrosive, humid, or dirty environments. Parylene can help extend operational life and improve reliability for connected devices, sensors, and control systems deployed in the field.

Download our industrial brochure

Parylene Properties

Several key properties make Parylene coating attractive for engineers evaluating protective coatings.

Excellent moisture and gas barrier performance: Parylene helps block humidity and environmental exposure that can degrade electronics over time.
High dielectric strength: It provides strong electrical insulation for sensitive and high-density electronics.
Low dielectric constant: This supports applications where signal integrity and electrical performance matter.
Chemical resistance: Parylene resists many solvents, fuels, and corrosive agents.
Conformality: It coats edges, corners, crevices, and complex surfaces more evenly than many liquid-applied alternatives.
Lightweight, ultra-thin protection: Effective performance can often be achieved at thicknesses of only a few microns.

Download Datasheet

How Parylene Coating Is Applied

The Parylene coating process uses chemical vapor deposition (CVD) to create a thin, conformal film at the molecular level. This process is one of the main reasons Parylene performs differently from traditional liquid coatings.

Vaporization: Solid Parylene dimer is heated and converted into vapor.
Pyrolysis: The vapor is further heated to form reactive monomer molecules.
Deposition: The monomer enters a vacuum chamber and polymerizes directly on exposed surfaces, forming a uniform coating.

Because the coating is deposited from a vapor phase, it can reach intricate geometries and coat components evenly without the pooling, shadowing, or edge-thinning often associated with liquid-applied coatings.

Types of Parylene Coating

Different types of Parylene are used depending on the application and performance requirements.

Parylene C: Commonly used because it offers a strong balance of moisture barrier, chemical resistance, and overall protection.
Parylene N: Known for strong dielectric performance and good conformality.
Parylene D: Selected when higher thermal stability is needed.

The right Parylene type depends on the environment, temperature range, barrier requirements, and electrical performance needs of the project.

Parylene vs. Liquid Conformal Coatings

Engineers often compare Parylene to traditional conformal coatings when selecting a protective solution. While both can protect electronics, they differ significantly in application method, coverage consistency, and performance.

Feature	Parylene	Liquid Coatings
Application method	Chemical vapor deposition	Spray, dip, or brush
Coverage uniformity	Highly uniform and conformal	Can vary by geometry and process
Typical film thickness	Ultra-thin	Usually thicker
Barrier protection	Strong moisture and chemical barrier	Performance varies by chemistry
Complex geometries	Excellent coverage	May experience pooling or shadowing

For a deeper comparison, review the blog post below.

Read Parylene vs. Liquid Coatings Blog Post

Is Parylene Right for Your Project?

Parylene is a strong choice when reliability, environmental protection, and coverage consistency are critical. It is often selected when failure would be expensive, dangerous, or difficult to repair.

Parylene Is a Strong Fit When:

Your device operates in humid, corrosive, or chemically challenging environments
Your electronics are miniaturized, dense, or geometrically complex
Long-term reliability is essential
Electrical insulation performance is a priority
The cost of failure is much higher than the cost of added protection

Another Coating May Be Better When:

Lowest upfront cost is the primary requirement
The environment is relatively mild
Thicker coatings are acceptable
Frequent rework, repair, or easy removal is important

Questions to Ask Before Choosing Parylene

What moisture, chemical, or corrosion risks will the product face?
What temperatures will it experience in use?
How dense or complex is the geometry of the assembly?
What electrical performance is required?
What are the reliability expectations across the product lifecycle?
What is the total cost of failure compared with the cost of coating?

Conclusion

Parylene coating is used in applications where engineers need thin, uniform, high-performance protection against moisture, chemicals, corrosion, and electrical stress. Its properties and deposition process make it especially valuable for electronics and components that must perform reliably in demanding environments.

If your project requires strong barrier protection, conformal coverage, and long-term durability, Parylene may be the right solution. The best way to decide is to evaluate your environment, reliability requirements, geometry, and lifecycle expectations against the strengths of the coating.

Need Help Choosing the Right Coating?

Not sure whether Parylene is the best fit for your application? Talk to an HZO expert to evaluate your environment, performance requirements, and design constraints.

Watch the webinar about Parylene’s proven corrosion resistance.

Watch on Demand

How Much Does Parylene Coating Cost? - All Things Considered

October 15, 2021 / by Mallory McGuinness-Hickey posted in Parylene, Value of Coatings

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Parylene coatings are known for robust protection from liquids, corrosion, chemicals, and strong electrical activity at a fraction of the thickness of alternative coatings, such as acrylics, epoxies, silicones, and urethanes. Additionally, Parylene is biocompatible, with beneficial optical properties, and delivers superior protection at 50% thickness of conventional coatings, such as acrylic conformal coating or epoxy. But, Parylene dimer and labor can be costly. So, design teams may hesitate to use them for high-reliability protection.

Read about why engineers choose Parylene.

Is Cost-Efficient Parylene Possible?

Many see Parylene coating as hard and costly to apply despite its proven performance. So, many assume it is suitable only for extreme, mission-critical situations. These include military, medical, and aviation applications.

What Are Other Common Misconceptions About Parylene?

Reworking and removing Parylene is impossible
Parylene coating equipment is too expensive and complicated to use
Masking is too complex and time-consuming to bother with
CVD coatings (chemical vapor deposition) entail long batch times. This raises labor costs and lowers throughput

These assumptions are unfounded. But Parylene coating is the most costly of all conformal coating options. So, choose a partner who can work within your budget. They should also help you estimate potential costs.

How to Calculate the Cost of Parylene

HZO capital equipment being used to lower Parylene coating cost

At HZO, we have crafted processes and procedures to cut the costs of Parylene coating. Yet, three factors are pertinent to the price regardless of whom you work with.

Parylene Type Affects the Cost

Common varieties, such as Parylene C and Parylene N, are less costly in raw coating material known as Parylene dimer. “Specialty types,” such as Parylene-AF4, will cost more but enable better UV and heat resistance. Consult HZO, a Parylene coating service, to find the best Parylene type for your project.

Parylene Masking Influences Price

Masking can be more complex with Parylene coatings, resulting in increased labor. However, changing your product's design can reduce costs. It would make it easier to coat and mask. HZO has industry-leading automated and semi-automated masking and demasking equipment. Working with us simplifies the process and cuts costs.

Quantity and Size of Objects that Require Coating

With Parylene, the objects you need to coat are placed into a vacuum chamber as part of the chemical vapor deposition (CVD) coating process. Each coating run will have a fixed cost. But, you can optimize the number of components coated in each run to lower the coating cost per item. (Meanwhile, HZO has built proprietary coating equipment that can house more items at once per run than any other Parylene company. This minimizes costs per run.)

Other Critical Considerations When Evaluating Parylene’s Price

Aside from considering upfront costs, to accurately assess Parylene’s coating expense, you must consider the coating’s value in terms of performance to preserve product function over time. In other words, the total cost of ownership is a critical consideration – upfront coating expense cannot fully measure value over a product’s life cycle. Parylene’s superior conformality and protection capabilities dramatically reduce field failures, warranty costs, and downtimes.

When you take the long-term view, the productivity and warranty savings that Parylene provides over time can make it the most economical coating option. There are other savings to consider when evaluating the price of conformal coatings, such as manufacturing costs. Conventional coatings entail cure cycles, VOC emissions, toxic byproducts, flammability, waste disposal, and health concerns. Parylene does not raise these safety and sustainability concerns as an environmentally friendly process.

Finally, investing in Parylene, with its exceptional dielectric strength, chemical and moisture resistance, and stress-free encapsulation, can substantially reduce the TCO to ruggedize components compared to other options.

Want to ensure HZO Parylene meets your specifications?

Download Datasheet

HZO Parylene Conformal Coating Services

If you want to evaluate Parylene coatings, contact our experts. They will provide a free DFM consultation.

IoT - Coating Consistency is Key

September 25, 2020 / by Mallory McGuinness-Hickey posted in Parylene, Coating Process, Coating Properties, Value of Coatings

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IoT sensors aggregate and send data to IoT dashboards, simplifying critical, complex decisions quickly. One key area where this is particularly true is the utilization of sensor data for predictive maintenance, a process that reduces downtime and lowers the total cost of ownership. Myriad other applications incorporate these “smart” sensors too.

Today, IoT sensors are ubiquitous, touching almost every aspect of life. Gas pressure sensors monitor pressure changes in oil, energy, and utility applications. Photoelectric devices (photo sensors) are now common in the consumer electronics vertical. Sensors are responsible for temperature monitoring, a typical use case for warehouse and inventory management, and HVAC systems monitoring.

Accelerometers detect subnormal industrial machine applications, while ultrasonic flow meters are coupled with IoT modules to send data about smart metering to a remote location. Moisture sensors have been critical in recent advances in smart farming, allowing for constant soil health monitoring. In the automotive sector, tunneling magnetoresistive sensors (TMR) are an increasingly popular way to measure mechanical displacement. And Particulate Matter sensors detect pollution in the industrial landscape and smart cities.

The chemical vapor deposition (CVD) process used to deposit Parylene conformal coatings can efficiently accommodate these complex surfaces. Parylene’s usefulness is primarily founded upon its ability to cover PCBA configurations with exposed internal surfaces, sharp edges, flat surfaces, points, and crevices with consistent coverage free of voids.

HZO PRO750 Parylene Coating Equipment

The Parylene Deposition Process – Consistent Coverage

Rather than dipping, spraying, or brushing pre-formulated layers onto PCBAs and other components, Parylene’s application method synthesizes the protective film in-process. This deposition system comprises a series of vacuum chambers that produce Parylene vapor, pyrolyze the vapor, then deposit the vapor as a polymer sequentially.

During the CVD process, gaseous Parylene penetrates the layers of a PCBA. Its vaporous consistency surrounds all areas as it builds coating protection along the exterior. The coating layers are substantially thinner than those provided by liquid conformal coating materials, enhancing reliability and functional versatility.

It has repeatedly been demonstrated that CVD is valuable for thin-film deposition on irregular PCBAs. CVD's Conformal layers are exceptionally uniform, even in the nanometer range. Because these coating layers are exceptionally thin, non-uniformity is minimal.

Reach out to an Expert

Choosing Parylene conformal coating services isn’t a failsafe decision, like anything else. Problems can occur with the process and the material. This is particularly true if the wrong Parylene type is used for a coating project while another type could provide better coverage. If you need a consultation to determine if Parylene is the right choice for your project, contact the HZO engineering team today, fill out a quote form, or leave a brief message.

Parylene Thickness - Industry Benchmarks, Cost, Effect on Properties

August 18, 2020 / by Mallory McGuinness-Hickey posted in Parylene, Coating Properties

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In the world of protective coatings, Parylene is a standout. Its unique, beneficial properties make it a great choice. Many Parylene types have distinct properties, like Parylene C, N, and F (VT-4 or AF-4, for example). By choosing a type, you can tailor Parylene to specific performance requirements.

How Does Parylene Thickness Affect Coating Properties?

The type of parylene dictates coating properties, while the thickness of the Parylene conformal coating determines its protection level. This includes electrical insulation, mechanical protection, and chemical resistance.

Electrical Insulation - A thicker coating usually has a higher dielectric strength. It can withstand greater electrical stress and prevent current leakage.

Mechanical Protection - Thicker coatings shield the substrate from damage, like abrasion better. They also resist mechanical stress.

Chemical Resistance - A thicker layer can delay the penetration of aggressive substances. It can also protect the substrate from corrosive environments for longer.

How Thick Does Parylene Need to Be?

How much Parylene do you need for your application? The answer depends on your design, choice of Parylene, and what environment you need protection from.

For example, applications requiring higher dielectric strength will require thicker Parylene layers, and this can be from 25 microns and above.

On the other hand, applications that are exposed to minimal moisture will typically require a coating greater than 2 microns.

What is the Best Parylene Thickness for My Industry? - Some Examples

Parylene Thickness Examples

Medical implants - Thickness varies depending on the use case and environment but typically can be seen in the 10 um to 20 um range.

Electronics - Thickness can vary from 2 microns up to and beyond 25um depending on the use case and environment of the product.

Aerospace components - A thicker application, often greater than 25 microns, offers enhanced protection from extreme environmental conditions.

How Thick Should Parylene Be in Different Environments?

Different environments demand specific barrier protection capabilities and, thus, different coating thicknesses. Analyze the threats in your application environment and the coating specs you must meet. Then, you can pinpoint the Parylene thickness you need. Here are some examples:

Moisture and Humidity - A Parylene coating as thin as2 microns can offer surface protection from moisture.

Submersion Protection: A Parylene coating from 5 microns and above will be able to protect most productions from freshwater submersion

Temperature and Humidity: Products that will experience a range of temperature and humidity changes over the lifetime of the product are typically coated at a thickness greater than 15 microns

Chemical and Solvent Resistance: Chemical exposure typically necessitates coatings over 10 microns to prevent permeation and ensure the integrity of the covered components.

Physical Abrasion: Parylene is a soft polymer and while it will not wipe off, it is not suitable to an environment where there will be continual abrasion of the coating.

By analyzing the environmental threats in your application environment and the coating specifications you must meet, you can pinpoint the Parylene thickness you need.

a coating expert double checking the parylene coating thickness on a PCB

How Do You Measure Parylene Thickness?

Coating thickness can be measured with various techniques. The industry standard method that HZO employes is to use spectral reflectance. This is done for every run in every one of our facilities. Additional methods such as contact Profilometry and Ellipsometry can also be used.

Spectral Reflectance

Spectral reflectance is used for measuring coating thickness by examining the interaction between light and matter at various wavelengths. Spectral reflectance measures how much light reflects from a thin coating over a range of wavelengths and is a non-destructive, non-contact method. Spectral reflectance is commonly used for coatings that range from around 1 to 50+ microns, most often on glass slide witness coupons and sometimes directly on a coated product with sufficiently flat and reflective surfaces.

Contact Profilometry

Contact Profilometry

With contact profilometry, a physical probe moves across the coating surface, registering variations in height to reveal thickness disparities. This mechanical method is respected for its accuracy and ability to produce detailed surface topography maps. However, the very contact nature of this technique might induce damage or introduce deformations to Parylene films, presenting a significant limitation so this Is not used on a a daily basis.

Ellipsometry

Ellipsometry, a non-destructive optical method, analyzes polarized light reflected from the coating surface. The ellipsometry tool infers film thickness by interpreting changes in the light's polarization state. Light interaction with the substrate complicates this analysis, often requiring the tool to perform complex calculations and it needs meticulous calibration to ensure accurate results, especially with non-uniform surfaces. Ellipsometry is more often used for sub-micron thickness coatings, especially on silicon wafer witness coupons.

At HZO, quality is top of mind. Since our inception, we've coated millions of components and haven't had one product return due to coating issues. Watch this video to learn more about our coating process.

Choose HZO as your Parylene Coating Partner

Are you wondering how thick the coating should be on your next project? No problem. Book a DFM consultation and speak to an engineer. They will tell you the next steps.

Solving Weather & Water Challenges For Smart Farms

May 12, 2020 / by Mallory McGuinness-Hickey posted in Parylene, Protection Capabilities, Thin Film Applications, Value of Coatings

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It’s a Small World, After All

The world’s population is projected to reach 8.5 billion by 2030, an unprecedented increase approaching fast. This looming surge will compound our current problem – more mouths to feed on a densely packed planet that isn’t growing any larger.

Even as available agricultural land shrinks and natural resources become more depleted, farmers must produce 70% more food by 2050.

Necessity is the mother of invention, especially when it comes to farming. After all, if the agricultural industry doesn’t adapt, we don’t eat. The task at hand for farmers is to produce more food with more precision while working with less.

IoT in Smart Farming: Connecting Dots

To adjust to these changes, the industry has introduced technology to agriculture, a practice known as smart farming. Intelligent devices collect and process information about emerging issues and environmental changes, enabling farmers to respond more quickly. Pulling this system together is the Internet of Things, connecting smart machines and integrated sensors to produce data-driven, data-enabled processes.

Information about the fertility of the soil, crop growth, weather conditions, and other variables can be used to track business status, equipment efficiency, and employee performance, offering valuable insights that can be used to optimize agricultural performance. As a result, work, waste, and risk are reduced, while cost management and capabilities are enhanced.

Hardware Security Implications in Smart Agriculture Pose Problems

While agricultural devices hold promise, no matter how smart the software may be, the success of the smart farming system is contingent upon how physically secure the hardware is. This is problematic for several reasons:

Without adequate protection, sensors can easily be damaged by wear and tear caused by constant exposure to drops, falls, heavy winds, or pounding rain.
Typical weather conditions, such as high temperatures, pollutants, condensation, and humidity, can cause immediate failure by a short circuit or a long, unpredictable shutdown due to corrosion.
To operate reliably, farm managers need to access information consistently. A single sensor failure could lead to a catastrophic period of downtime at worst. At best, failing devices create the need for continuous maintenance and replacement.

one phone underwater that is still working because of HZO protection and another that is dead because of water damage

Protecting Smart Farming Equipment Has Never Been This Important

The onus falls on the agricultural industry to achieve more precision and a higher level of performance as it struggles to meet the demands of our population. To farmers, physically robust hardware is more important than ever.

Weather stations located across fields offer insight into climate conditions, the optimal choice of crops, and potential actions that, when taken, could improve farming capacity. Meanwhile, sensors attached to cattle are helping farmers understand changes in health and activity levels for each animal and, collectively, the status of the entire herd.

Crop management devices produce data about crop health, precipitation, and temperature fluctuations, allowing farmers to mitigate risk and increase yield proactively. This kind of cognizance is gleaned from smart farming sensors, provided these devices can predictably perform in an unpredictable environment.

Overcoming Challenges to Device Security In Smart Farming with Parylene Thin-Film Coatings

Considered a “best-in-class” conformal coating in electronic, industrial, medical, and engineering industries, Parylene is a thin-film electronic protection solution that can address agricultural challenges. Applied with a vacuum deposition technique, Parylene coatings achieve dependable coverage free from imperfections like cracks or voids. The coating uniformly conforms to device topography, completely penetrating spaces as narrow as <0.01 mm.

Additionally, Parylene has good heat endurance. For example, Parylene C can offer durable environmental protection for ten years at 80°C. Providing mission-critical protection at thicknesses on the micron level, Parylene can endure temperatures and weather conditions that traditionally have been hurdles for smart farming devices.

If you have been tasked with designing or manufacturing smart farming devices that the industry can depend on, Parylene is an excellent way to achieve critical reliability. Please contact us today if you’d like to learn more about our Parylene solution.

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