Protecting medical devices

Features - Coatings

Thin-film conformal coatings build strong barrier protection against environmental threats that could cause medical device failure.

August 5, 2021


Any interaction with a healthcare provider is likely to involve one or more digital devices, sophisticated diagnostic equipment, medical instruments, and/or software applications that are connected to the Internet. These comprise the Internet of Medical Things (IoMT) – a connected infrastructure of health systems and services that collect, analyze, and transmit health data to improve efficiencies, lower care costs, and drive better healthcare outcomes.

Dependable devices required

Regardless of the device or equipment, the IoMT requires that they’re sturdy, can operate dependably in all harsh medical environments including cleaning solutions, bodily fluids, and more, and can operate at full capacity with very low power. For device protection, coatings are the clear answer for their conformality and minimal profile. Every coating, however, is not created equal. Silicones, acrylics, and epoxies can be unreliable, ineffective, toxic, and costly. Thin-film conformal coatings have been identified as a best-case solution for electronics protection. Known for their excellent moisture and chemical resistance, thin-film conformal coatings uniquely build strong barrier protection against environmental threats that could cause electronic failures, such as salt fog, humidity, pollutants, liquids and corrosives, and contaminants on a nano or micron scale.

Parylene and plasma-based thin-film nano coatings are next-generation conformal coatings that provide superior stability tailored to specific operating environments at a competitive price point. Based on tested and proven material science, these polymeric films are typically applied at sub-25µm thickness, which may allow manufacturers to avert unnecessary weight and bulk during device design. As chips and devices become smaller and more ubiquitous, a thinner, lighter coating can enhance device functionality and patient comfort.

Traditional conformal coatings can require a curing process to harden the films which can release potentially harmful solvents. Parylene and plasma-based nano coatings don’t require curing. Parylene and plasma-based nano coatings are applied via chemical vapor deposition (CVD), which delivers the consistency, quality, and repeatability required in IoMT product manufacturing.

Parylene’s deposition process makes it a superior coating choice for the IoMT. Where other coatings start as a liquid, are deposited, and then dried, Parylene is a solid initially. It’s transformed into a vapor via CVD and then ultimately applied to the target substrate, such as a printed circuit board (PCB). The coating is done in a closed system under a controlled vacuum. Due to the nature of CVD, no additional cure process or steps are required. In its vapor state, Parylene will go everywhere in the vacuum chamber, allowing it to conformally coat all component configurations with sharp edges, points, flat surfaces, and crevices, uniformly without voids. Due to the CVD process, the Parylene coating will have a uniform thickness across the entire surface.

Parylene is also considered a green chemistry. Because there are no catalysts or solvents involved in the Parylene vacuum deposition process, the coating is pure and free from impurities. Parylene is chemically inert and non-toxic and produces no leachable ingredients.

Parylene is a U.S. FDA-approved Class VI polymer, a biocompatibility rating suitable for human implantable devices. Its versatility and reliability has made it the coating choice for many biomedical suppliers and medical device manufacturers. Electronics manufacturers appreciate Parylene’s ability to protect and improve the overall quality of microcontrollers and sensors that are critical for edge and IoT systems and their communications components.

During the pandemic, the means for care were forced to change across all disciplines, including medical doctors, nurse practitioners, physician’s assistants, physical and occupational therapists, social workers, psychiatrists, and psychologists. Individuals with chronic conditions such as diabetes and heart disease have been monitored with blood glucose monitors, EKGs, and pulse oximeters. Newly discharged patients are also benefiting from monitoring devices that facilitate earlier hospital discharge.

The world is ready to reach the other side of the pandemic, and thanks to the advancements in technology and coatings, manufacturers and patients alike can look forward to smarter, smaller, and more durable devices and instruments to support the IoMT in the years ahead.

HZO Inc.

About the author: James Tosh is vice president of application engineering at HZO Inc. In 2014 he joined HZO where his main role is working directly with customers throughout the life of their products from ideation to production.