Polyimide Coating Knowledge

Polyimide (PI) Coating

Polyimide (PI) is a high‑performance polymer widely used for interventional medical devices, aerospace and electronic components. Boasting great thermal stability, mechanical toughness, chemical resistance and dielectric properties, polyimide coating serves as protective and functional layers for catheters, guidewires and micro‑medical tubing. It withstands common medical sterilization methods, tolerates repeated bending in complex vascular pathways, and shows good biological inertness after medical‑grade optimization, making it compatible with human blood and tissues. Its surface can also be modified for hydrophilic lubrication or drug‑loading, while its insulation capability supports electrophysiology and diagnostic device manufacturing.

Traditional dip‑coating processes frequently produce polyimide coating defects such as uneven thickness, edge buildup and bubbles on miniature precision medical parts. Ultrasonic spraying atomizes polyimide solution into fine droplets to deposit thin, uniform, pinhole‑free films with stable repeatability. This technology enables accurate thickness control, reduces raw material waste, and fits both laboratory research and large‑scale medical‑grade production for fine tubes, guidewires and small interventional components.

There are practical limitations for polyimide coating in real‑world medical manufacturing. Pure polyimide is not inherently hydrophilic, so extra surface modification or top‑coats are required to achieve low‑friction performance under aqueous conditions. Strict viscosity and process parameter control are necessary to avoid pinholes and orange‑peel surface defects. Besides, medical‑grade polyimide coatings must complete full biocompatibility validation to satisfy relevant medical regulatory standards before clinical application.