Dendritic discharge patterns in a polymer may look stunning, as the image here attests, but if you're making a catheter hub, as opposed to a random act of art, it can lead to catastrophic device failure. Cambridge Polymer Group (CPG), a contract materials research lab headquartered in Boston, MA, recently shared a case study of a customer whose catheter hubs were cracking during the manufacturing process. The group determined that the sterilization technology used by the manufacturer was causing the problem and found a solution.
The medical device manufacturer was using E-beam technology to terminally sterilize the polycarbonate in which the electronics and catheter are embedded. This sterilization technique, which involves bombarding the workpiece with high-energy electrons, is commonly used in medical manufacturing, but it has drawbacks when treating certain materials. The high flux and beam energies cause rapid charge buildup on components, explains CPG, and if it is uncompensated, the charge can arc between the charged surface and metal contacts, resulting in fracture of the insulating polymer. The effect is similar to a lightning storm.