目的 揭示可植入电子器件(IEDs)封装用聚酰亚胺材料中水的传输行为及阻滞性能劣化机制，为寻求该封装材料的阻滞性能和寿命的评价方法、提高IEDs的保护能力提供基础试验数据和理论参考。方法 选择模拟体液为研究介质，采用称重试验、电化学阻抗谱(EIS)、形貌表征和孔隙率测定等技术手段，研究水在聚酰亚胺涂层中的传输行为及涂层阻滞性能的劣化机制，同时探讨生物大分子对涂层中水传输行为的影响。结果 涂层中水的传输行为包括4个阶段:第一阶段为水在涂层表面的润湿过程，此阶段吸水率在短时间内迅速增加;第二阶段为Fick扩散阶段，此阶段水的扩散系数仅为5.6×10^–15 cm/s;第三阶段，吸水率突增，此阶段有结合水形成;第四阶段，吸水达到饱和，水以自由水和结合水两种状态存在。涂层阻滞性能劣化是由于涂层在基体上的附着力较小，仅为1.78 MPa，当水等侵蚀性粒子进入涂层时，会导致涂层起泡，阻滞性能劣化。此外，由于涂层平均孔径小于体液中生物大分子的尺寸，吸附在涂层表面的大分子对水在涂层中的传输起到阻滞作用。结论 聚酰亚胺涂层中水的传输速度较慢，而且体液中的大分子会进一步阻止水的进入，故聚酰亚胺是较为理想的体内封装材料，通过提升涂层与基体的结合力，可以提高涂层的使役寿命。

This paper aims to reveal the water transport behavior and the degradation mechanism of the retardation performance of the polyimide materials used in the encapsulation of implantable electronic devices (IEDs), and provide a method for seeking the evaluation methods of the retardation performance and lifetime of the packaging materials, and to improve the protection ability of IEDs basic experimental data and theoretical references. Select simulated body fluid as the research medium, and use weighing experiment, electrochemical impedance spectroscopy (EIS), morphology characterization and porosity measurement and other technical means to study the water transmission behavior in the polyimide coating and the coating retardation performance. At the same time, the influence of biological macromolecules on the water transport behavior in the coating is discussed. The results show that water transport behavior includes four stages:in the first stage, water absorption rate increases rapidly in a short time, which means the coating surface is wet by water. In the second stage, the transport process of water conforms to Fick’s diffusion. The diffusion coefficient of water at this stage is only 5.6×10–15 cm/s. In the third stage, the water absorption rate increases suddenly, which is because that water molecules interact with the polymer to form bound water. The coating has reached the saturation state in the fourth stage. Water exists in two states:free water and bound water. The deterioration of the coating retardation performance is due to the low adhesion of the coating on the substrate, which is only 1.78 MPa. When corrosive particles such as water enter the coating, the coating will foam and the retardation performance will deteriorate. Besides, when water and other corrosive particles enter the coating, it will cause the coating to foam and degrade the retardation performance. As a result, we can draw the conclusion that the water transport in the polyimide coating lowly, and the macromolecules in the body fluid will further prevent the penetration of water. Therefore, polyimide is an ideal internal encapsulation material, and the service life of the coating can be increased by improving the bonding force between the coating and the substrate.