Extending the lifecycle of implantable electronic devices
Scientists have focused on the protection coating of devices such as cardiac pacemakers and identified the failure mechanism of medical silicone rubber. Water diffusion plays a crucial role in the crack evolution of the coating.
Implantable electronic devices (IEDs) are increasingly used in medical treatment and diagnose for physiological monitoring. However, encapsulation of IEDs still faces significant challenges as full prevention of body fluid penetration into the coating remains widely unsolved.
To enable an extended lifecycle for IEDs, the impact of water transport on the failure mechanism of silicone rubber coating was systematically investigated in the new study. Water absorption and morphology characterisation firstly illustrated the water diffusion model and demonstrate the presence of cracks inside the silicone rubber coating, respectively. Subsequent electrochemical characterisations further verified a three-step water penetration behavior in the coating/substrate system and quantified the crack growth and evolution.
Crack propagation responsible for coating failure
By further experimental and finite element studies, it was proved that crack propagation is responsible for coating failure in IEDs, while a comprehensive failure mechanism of medical silicone rubber coating in simulated body fluid has also been uncovered in a detailed manner. According to the researchers, such a clear elucidation of failure mechanism for silicone rubber coating may be greatly beneficial for future coating material design for IEDs.
The study has been published in Progress in Organic Coatings, Volume 159, October 2021.
