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 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 this study. Water absorption and morphology characterization firstly illustrate the water diffusion model and demonstrate the presence of cracks inside the silicone rubber coating, respectively. Subsequent electrochemical characterizations further verify a three-step water penetration behavior in the coating/substrate system, and meanwhile quantify the crack growth and evolution. By further experimental and finite element studies, it is 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 is also uncovered in a detailed manner for the first time. Such a clear elucidation of failure mechanism for silicone rubber coating is greatly beneficial for future packaging material design for IEDs.

植入式电子设备 (IED) 越来越多地用于医疗和诊断以进行生理监测。然而，IED 的封装仍然面临重大挑战，因为完全防止体液渗入涂层仍未解决。为了延长 IED 的生命周期，本研究系统地研究了水传输对硅橡胶涂层失效机制的影响。吸水率和形态表征首先说明了水扩散模型，并分别证明了硅橡胶涂层内部裂纹的存在。随后的电化学表征进一步验证了涂层/基材系统中的三步水渗透行为，同时量化了裂纹的增长和演变。通过进一步的实验和有限元研究，证明裂纹扩展是IED涂层失效的原因，同时也首次详细揭示了模拟体液中医用硅橡胶涂层的综合失效机制。对硅橡胶涂层失效机理的如此清晰的阐明对于未来 IED 的包装材料设计非常有益。